diff --git a/src/xml/composers.rs b/src/xml/composers.rs
index 3313a56..949bb65 100644
--- a/src/xml/composers.rs
+++ b/src/xml/composers.rs
@@ -3,12 +3,18 @@ use std::io;
 use tokio::io::{AsyncWrite, AsyncWriteExt};
 
 use super::{
-    AttValue, AttValueData, CDEnd, CDSect, CDStart, CData, Char, CharData, Comment, DeclSep,
-    DefaultAttName, DoctypeDecl, Document, Element, EntityValue, EntityValueData, Eq, ExtSubset,
-    ExtSubsetDecl, IntSubset, LocalPart, MarkupDecl, Misc, NCName, NSAttName, Name, NameChar,
-    NameStartChar, Names, Nmtoken, Nmtokens, PITarget, Prefix, PrefixedAttName, PrefixedName,
-    Prolog, PubidChar, PubidLiteral, QName, SDDecl, SystemLiteral, UnprefixedName, VersionInfo,
-    VersionNum, XMLDecl, PI, S,
+    AttDef, AttDefName, AttType, AttValue, AttValueData, AttlistDecl, Attribute, CDEnd, CDSect,
+    CDStart, CData, Char, CharData, CharRef, Children, ChildrenKind, Choice, Comment,
+    ConditionalSect, Content, ContentItem, Contentspec, Cp, CpKind, DeclSep, DefaultAttName,
+    DefaultDecl, DoctypeDecl, Document, ETag, Element, Elementdecl, EmptyElemTag, EncName,
+    EncodingDecl, EntityDecl, EntityDef, EntityRef, EntityValue, EntityValueData, EnumeratedType,
+    Enumeration, Eq, ExtParsedEnt, ExtSubset, ExtSubsetDecl, ExtSubsetDeclaration, ExternalID,
+    GEDecl, Ignore, IgnoreSect, IgnoreSectContents, IncludeSect, IntSubset, LocalPart, MarkupDecl,
+    Misc, Mixed, NCName, NDataDecl, NSAttName, Name, NameChar, NameStartChar, Names, Nmtoken,
+    Nmtokens, NotationDecl, NotationDeclID, NotationType, Occurence, PEDecl, PEDef, PEReference,
+    PITarget, Prefix, PrefixedAttName, PrefixedName, Prolog, PubidChar, PubidLiteral, PublicID,
+    QName, Reference, SDDecl, STag, Seq, StringType, SystemLiteral, TextDecl, TokenizedType,
+    UnprefixedName, VersionInfo, VersionNum, XMLDecl, PI, S,
 };
 
 /// Compact Composer trait, can create different trait later for pretty composition
@@ -508,10 +514,10 @@ impl<'s> Composer<'s> for XMLDecl<'s> {
     {
         writer.write_all("<?xml".as_bytes()).await?;
         self.version_info.write(writer).await?;
-        if let Some(encoding_decl) = self.encoding_decl {
+        if let Some(encoding_decl) = &self.encoding_decl {
             encoding_decl.write(writer).await?
         }
-        if let Some(sd_decl) = self.sd_decl {
+        if let Some(sd_decl) = &self.sd_decl {
             sd_decl.write(writer).await?
         }
         writer.write_all("?>".as_bytes()).await?;
@@ -594,11 +600,11 @@ impl<'s> Composer<'s> for DoctypeDecl<'s> {
         writer.write_all("<!DOCTYPE".as_bytes()).await?;
         S.write(writer).await?;
         self.name.write(writer).await?;
-        if let Some(external_id) = self.external_id {
+        if let Some(external_id) = &self.external_id {
             S.write(writer).await?;
             external_id.write(writer).await?;
         }
-        if let Some(int_subset) = self.int_subset {
+        if let Some(int_subset) = &self.int_subset {
             writer.write_all("[".as_bytes()).await?;
             int_subset.write(writer).await?;
             writer.write_all("]".as_bytes()).await?;
@@ -664,7 +670,7 @@ impl<'s> Composer<'s> for ExtSubset<'s> {
     where
         W: Unpin + AsyncWrite,
     {
-        if let Some(text_decl) = self.text_decl {
+        if let Some(text_decl) = &self.text_decl {
             text_decl.write(writer).await?
         }
         self.ext_subset_decl.write(writer).await?;
@@ -680,13 +686,11 @@ impl<'s> Composer<'s> for ExtSubsetDecl<'s> {
     {
         for declaration in self {
             match declaration {
-                super::ExtSubsetDeclaration::MarkupDecl(markup_decl) => {
-                    markup_decl.write(writer).await?
+                ExtSubsetDeclaration::MarkupDecl(markup_decl) => markup_decl.write(writer).await?,
+                ExtSubsetDeclaration::ConditionalSect(conditional_sect) => {
+                    Box::pin(conditional_sect.write(writer)).await?
                 }
-                super::ExtSubsetDeclaration::ConditionalSect(conditional_sect) => {
-                    conditional_sect.write(writer).await?
-                }
-                super::ExtSubsetDeclaration::DeclSep(decl_sep) => decl_sep.write(writer).await?,
+                ExtSubsetDeclaration::DeclSep(decl_sep) => decl_sep.write(writer).await?,
             }
         }
         Ok(())
@@ -724,12 +728,768 @@ impl Composer<'_> for SDDecl {
     }
 }
 
+// (Productions 33 through 38 have been removed.)
+
 /// [39]   	element	   ::=   	EmptyElemTag | STag content ETag
 impl<'s> Composer<'s> for Element<'s> {
     async fn write<W>(&self, writer: &mut W) -> io::Result<()>
     where
         W: Unpin + AsyncWrite,
     {
-        todo!()
+        match self {
+            Element::Empty(empty_elem_tag) => empty_elem_tag.write(writer).await?,
+            Element::NotEmpty(s_tag, content, e_tag) => {
+                s_tag.write(writer).await?;
+                content.write(writer).await?;
+                e_tag.write(writer).await?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [12]   	STag	   ::=   	'<' QName (S Attribute)* S? '>'
+/// [40]   	STag	   ::=   	'<' Name (S Attribute)* S? '>'
+impl<'s> Composer<'s> for STag<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<".as_bytes()).await?;
+        self.name.write(writer).await?;
+        for attribute in &self.attributes {
+            S.write(writer).await?;
+            attribute.write(writer).await?;
+        }
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [15]   	Attribute	   ::=   	NSAttName Eq AttValue | QName Eq AttValue
+impl<'s> Composer<'s> for Attribute<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            Attribute::NamespaceDeclaration { ns_name, value } => {
+                ns_name.write(writer).await?;
+                Eq.write(writer).await?;
+                value.write(writer).await?;
+            }
+            Attribute::Attribute { name, value } => {
+                name.write(writer).await?;
+                Eq.write(writer).await?;
+                value.write(writer).await?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [13]   	ETag	   ::=   	'</' QName S? '>'
+impl<'s> Composer<'s> for ETag<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("</".as_bytes()).await?;
+        self.name.write(writer).await?;
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [43]   	content	   ::=   	CharData? ((element | Reference | CDSect | PI | Comment) CharData?)*
+impl<'s> Composer<'s> for Content<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        if let Some(char_data) = &self.char_data {
+            char_data.write(writer).await?;
+        }
+        for (content, char_data) in &self.content {
+            match content {
+                ContentItem::Element(element) => Box::pin(element.write(writer)).await?,
+                ContentItem::Reference(reference) => reference.write(writer).await?,
+                ContentItem::CDSect(cd_sect) => cd_sect.write(writer).await?,
+                ContentItem::PI(pi) => pi.write(writer).await?,
+                ContentItem::Comment(comment) => comment.write(writer).await?,
+            }
+            if let Some(char_data) = char_data {
+                char_data.write(writer).await?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [14]   	EmptyElemTag	   ::=   	'<' QName (S Attribute)* S? '/>'
+impl<'s> Composer<'s> for EmptyElemTag<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<".as_bytes()).await?;
+        self.name.write(writer).await?;
+        for attribute in &self.attributes {
+            S.write(writer).await?;
+            attribute.write(writer).await?;
+        }
+        writer.write_all("/>".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [17]   	elementdecl	   ::=   	'<!ELEMENT' S QName S contentspec S? '>'
+impl<'s> Composer<'s> for Elementdecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<!ELEMENT".as_bytes()).await?;
+        S.write(writer).await?;
+        self.name.write(writer).await?;
+        S.write(writer).await?;
+        self.contentspec.write(writer).await?;
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [46]   	contentspec	   ::=   	'EMPTY' | 'ANY' | Mixed | children
+impl<'s> Composer<'s> for Contentspec<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            Contentspec::Empty => writer.write_all("EMPTY".as_bytes()).await?,
+            Contentspec::Any => writer.write_all("ANY".as_bytes()).await?,
+            Contentspec::Mixed(mixed) => mixed.write(writer).await?,
+            Contentspec::Children(children) => children.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// Occurence ::= ('?' | '*' | '+')?
+impl Composer<'_> for Occurence {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            Occurence::Once => {}
+            Occurence::Optional => writer.write_all("?".as_bytes()).await?,
+            Occurence::Many0 => writer.write_all("*".as_bytes()).await?,
+            Occurence::Many1 => writer.write_all("+".as_bytes()).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [47]   	children	   ::=   	(choice | seq) ('?' | '*' | '+')?
+impl<'s> Composer<'s> for Children<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match &self.kind {
+            ChildrenKind::Choice(choice) => choice.write(writer).await?,
+            ChildrenKind::Seq(seq) => seq.write(writer).await?,
+        }
+        self.occurence.write(writer).await?;
+        Ok(())
+    }
+}
+
+/// [18]   	cp	   ::=   	(QName | choice | seq) ('?' | '*' | '+')?
+impl<'s> Composer<'s> for Cp<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match &self.kind {
+            CpKind::Name(q_name) => q_name.write(writer).await?,
+            CpKind::Choice(choice) => Box::pin(choice.write(writer)).await?,
+            CpKind::Seq(seq) => Box::pin(seq.write(writer)).await?,
+        }
+        self.occurence.write(writer).await?;
+        Ok(())
+    }
+}
+
+/// [49]   	choice	   ::=   	'(' S? cp ( S? '|' S? cp )+ S? ')'
+impl<'s> Composer<'s> for Choice<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("(".as_bytes()).await?;
+        let mut first = true;
+        for cp in &self.0 {
+            if !first {
+                writer.write_all("|".as_bytes()).await?;
+            }
+            cp.write(writer).await?;
+            if first {
+                first = false
+            }
+        }
+        writer.write_all(")".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [50]   	seq	   ::=   	'(' S? cp ( S? ',' S? cp )* S? ')'
+impl<'s> Composer<'s> for Seq<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("(".as_bytes()).await?;
+        let mut first = true;
+        for cp in &self.0 {
+            if !first {
+                writer.write_all(",".as_bytes()).await?;
+            }
+            cp.write(writer).await?;
+            if first {
+                first = false
+            }
+        }
+        writer.write_all(")".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [19]   	Mixed	   ::=   	'(' S? '#PCDATA' (S? '|' S? QName)* S? ')*' | '(' S? '#PCDATA' S? ')'
+impl<'s> Composer<'s> for Mixed<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("(#PCDATA".as_bytes()).await?;
+        if !self.0.is_empty() {
+            for q_name in &self.0 {
+                writer.write_all("|".as_bytes()).await?;
+                q_name.write(writer).await?;
+            }
+            writer.write_all(")*".as_bytes()).await?;
+        } else {
+            writer.write_all(")".as_bytes()).await?;
+        }
+        Ok(())
+    }
+}
+
+/// [20]   	AttlistDecl	   ::=   	'<!ATTLIST' S QName AttDef* S? '>'
+impl<'s> Composer<'s> for AttlistDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<!ATTLIST".as_bytes()).await?;
+        S.write(writer).await?;
+        self.element_type.write(writer).await?;
+        for att_def in &self.att_defs {
+            att_def.write(writer).await?;
+        }
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [21]   	AttDef	   ::=   	S (QName | NSAttName) S AttType S DefaultDecl
+impl<'s> Composer<'s> for AttDef<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        S.write(writer).await?;
+        match &self.name {
+            AttDefName::QName(q_name) => q_name.write(writer).await?,
+            AttDefName::NSAttName(ns_att_name) => ns_att_name.write(writer).await?,
+        }
+        S.write(writer).await?;
+        self.att_type.write(writer).await?;
+        S.write(writer).await?;
+        self.default_decl.write(writer).await?;
+        Ok(())
+    }
+}
+
+/// [54]   	AttType	   ::=   	StringType | TokenizedType | EnumeratedType
+impl<'s> Composer<'s> for AttType<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            AttType::StringType => StringType.write(writer).await?,
+            AttType::TokenizedType(tokenized_type) => tokenized_type.write(writer).await?,
+            AttType::EnumeratedType(enumerated_type) => enumerated_type.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [55]   	StringType	   ::=   	'CDATA'
+impl Composer<'_> for StringType {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("CDATA".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [56]   	TokenizedType	   ::=   	'ID' | 'IDREF' | 'IDREFS' | 'ENTITY' | 'ENTITIES' | 'NMTOKEN' | 'NMTOKENS'
+impl Composer<'_> for TokenizedType {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            TokenizedType::ID => writer.write_all("ID".as_bytes()).await?,
+            TokenizedType::IDRef => writer.write_all("IDREF".as_bytes()).await?,
+            TokenizedType::IDRefs => writer.write_all("IDREFS".as_bytes()).await?,
+            TokenizedType::Entity => writer.write_all("ENTITY".as_bytes()).await?,
+            TokenizedType::Entities => writer.write_all("ENTITIES".as_bytes()).await?,
+            TokenizedType::NMToken => writer.write_all("NMTOKEN".as_bytes()).await?,
+            TokenizedType::NMTokens => writer.write_all("NMTOKENS".as_bytes()).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [57]   	EnumeratedType	   ::=   	NotationType | Enumeration
+impl<'s> Composer<'s> for EnumeratedType<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            EnumeratedType::NotationType(notation_type) => notation_type.write(writer).await?,
+            EnumeratedType::Enumeration(enumeration) => enumeration.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [58]   	NotationType	   ::=   	'NOTATION' S '(' S? Name (S? '|' S? Name)* S? ')'
+impl<'s> Composer<'s> for NotationType<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("NOTATION".as_bytes()).await?;
+        S.write(writer).await?;
+        writer.write_all("(".as_bytes()).await?;
+        let mut first = true;
+        for name in &self.0 {
+            if !first {
+                writer.write_all("|".as_bytes()).await?;
+            }
+            name.write(writer).await?;
+            if first {
+                first = false
+            }
+        }
+        writer.write_all(")".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [59]   	Enumeration	   ::=   	'(' S? Nmtoken (S? '|' S? Nmtoken)* S? ')'
+impl<'s> Composer<'s> for Enumeration<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("(".as_bytes()).await?;
+        let mut first = true;
+        for nm_token in &self.0 {
+            if !first {
+                writer.write_all("|".as_bytes()).await?;
+            }
+            nm_token.write(writer).await?;
+            if first {
+                first = false
+            }
+        }
+        writer.write_all(")".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [60]   	DefaultDecl	   ::=   	'#REQUIRED' | '#IMPLIED' | (('#FIXED' S)? AttValue)
+impl<'s> Composer<'s> for DefaultDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            DefaultDecl::Required => writer.write_all("#REQUIRED".as_bytes()).await?,
+            DefaultDecl::Implied => writer.write_all("#IMPLIED".as_bytes()).await?,
+            DefaultDecl::Fixed(fixed, att_value) => {
+                if *fixed {
+                    writer.write_all("#FIXED".as_bytes()).await?;
+                    S.write(writer).await?;
+                }
+                att_value.write(writer).await?
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [61]   	conditionalSect	   ::=   	includeSect | ignoreSect
+impl<'s> Composer<'s> for ConditionalSect<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            ConditionalSect::IncludeSect(include_sect) => include_sect.write(writer).await?,
+            ConditionalSect::IgnoreSect(ignore_sect) => ignore_sect.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [62]   	includeSect	   ::=   	'<![' S? 'INCLUDE' S? '[' extSubsetDecl ']]>'
+impl<'s> Composer<'s> for IncludeSect<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<![INCLUDE[".as_bytes()).await?;
+        self.0.write(writer).await?;
+        writer.write_all("]]>".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [63]   	ignoreSect	   ::=   	'<![' S? 'IGNORE' S? '[' ignoreSectContents* ']]>'
+impl<'s> Composer<'s> for IgnoreSect<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<![IGNORE[".as_bytes()).await?;
+        for ignore_sect_contents in &self.0 {
+            ignore_sect_contents.write(writer).await?;
+        }
+        writer.write_all("]]>".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [64]   	ignoreSectContents	   ::=   	Ignore ('<![' ignoreSectContents ']]>' Ignore)*
+impl<'s> Composer<'s> for IgnoreSectContents<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        self.ignore.write(writer).await?;
+        for (ignore_sect_contents, ignore) in &self.ignore_list {
+            writer.write_all("<![".as_bytes()).await?;
+            Box::pin(ignore_sect_contents.write(writer)).await?;
+            writer.write_all("]]>".as_bytes()).await?;
+            ignore.write(writer).await?;
+        }
+        Ok(())
+    }
+}
+
+/// [65]   	Ignore	   ::=   	Char* - (Char* ('<![' | ']]>') Char*)
+impl<'s> Composer<'s> for Ignore<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all(self.0.as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [66]   	CharRef	   ::=   	'&#' [0-9]+ ';' | '&#x' [0-9a-fA-F]+ ';'
+impl<'s> Composer<'s> for CharRef<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            CharRef::Decimal(decimal) => {
+                writer.write_all("&#".as_bytes()).await?;
+                writer.write_all(decimal.as_bytes()).await?;
+                writer.write_all(";".as_bytes()).await?;
+            }
+            CharRef::Hexadecimal(hexadecimal) => {
+                writer.write_all("&#x".as_bytes()).await?;
+                writer.write_all(hexadecimal.as_bytes()).await?;
+                writer.write_all(";".as_bytes()).await?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [67]   	Reference	   ::=   	EntityRef | CharRef
+impl<'s> Composer<'s> for Reference<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            Reference::EntityRef(entity_ref) => entity_ref.write(writer).await?,
+            Reference::CharRef(char_ref) => char_ref.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [68]   	EntityRef	   ::=   	'&' Name ';'
+impl<'s> Composer<'s> for EntityRef<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("&".as_bytes()).await?;
+        self.0.write(writer).await?;
+        writer.write_all(";".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [69]   	PEReference	   ::=   	'%' Name ';'
+impl<'s> Composer<'s> for PEReference<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("%".as_bytes()).await?;
+        self.0.write(writer).await?;
+        writer.write_all(";".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [70]   	EntityDecl	   ::=   	GEDecl | PEDecl
+impl<'s> Composer<'s> for EntityDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            EntityDecl::GEDecl(ge_decl) => ge_decl.write(writer).await?,
+            EntityDecl::PEDecl(pe_decl) => pe_decl.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [71]   	GEDecl	   ::=   	'<!ENTITY' S Name S EntityDef S? '>'
+impl<'s> Composer<'s> for GEDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<!ENTITY".as_bytes()).await?;
+        S.write(writer).await?;
+        self.name.write(writer).await?;
+        S.write(writer).await?;
+        self.entity_def.write(writer).await?;
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [72]   	PEDecl	   ::=   	'<!ENTITY' S '%' S Name S PEDef S? '>'
+impl<'s> Composer<'s> for PEDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<!ENTITY".as_bytes()).await?;
+        S.write(writer).await?;
+        writer.write_all("%".as_bytes()).await?;
+        S.write(writer).await?;
+        self.name.write(writer).await?;
+        S.write(writer).await?;
+        self.pe_def.write(writer).await?;
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [73]   	EntityDef	   ::=   	EntityValue | (ExternalID NDataDecl?)
+impl<'s> Composer<'s> for EntityDef<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            EntityDef::EntityValue(entity_value) => entity_value.write(writer).await?,
+            EntityDef::ExternalID {
+                external_id,
+                n_data_decl,
+            } => {
+                external_id.write(writer).await?;
+                if let Some(n_data_decl) = n_data_decl {
+                    n_data_decl.write(writer).await?;
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [74]   	PEDef	   ::=   	EntityValue | ExternalID
+impl<'s> Composer<'s> for PEDef<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            PEDef::EntityValue(entity_value) => entity_value.write(writer).await?,
+            PEDef::ExternalID(external_id) => external_id.write(writer).await?,
+        }
+        Ok(())
+    }
+}
+
+/// [75]   	ExternalID	   ::=   	'SYSTEM' S SystemLiteral | 'PUBLIC' S PubidLiteral S SystemLiteral
+impl<'s> Composer<'s> for ExternalID<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        match self {
+            ExternalID::SYSTEM { system_identifier } => {
+                writer.write_all("SYSTEM".as_bytes()).await?;
+                S.write(writer).await?;
+                system_identifier.write(writer).await?;
+            }
+            ExternalID::PUBLIC {
+                public_identifier,
+                system_identifier,
+            } => {
+                writer.write_all("PUBLIC".as_bytes()).await?;
+                S.write(writer).await?;
+                public_identifier.write(writer).await?;
+                S.write(writer).await?;
+                system_identifier.write(writer).await?;
+            }
+        }
+        Ok(())
+    }
+}
+
+/// [76]   	NDataDecl	   ::=   	S 'NDATA' S Name
+impl<'s> Composer<'s> for NDataDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        S.write(writer).await?;
+        writer.write_all("NDATA".as_bytes()).await?;
+        S.write(writer).await?;
+        self.0.write(writer).await?;
+        Ok(())
+    }
+}
+
+/// [77]   	TextDecl	   ::=   	'<?xml' VersionInfo? EncodingDecl S? '?>'
+impl<'s> Composer<'s> for TextDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<?xml".as_bytes()).await?;
+        if let Some(version_info) = &self.version_info {
+            version_info.write(writer).await?;
+        }
+        self.encoding_decl.write(writer).await?;
+        writer.write_all("?>".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [78]   	extParsedEnt	   ::=   	TextDecl? content
+impl<'s> Composer<'s> for ExtParsedEnt<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        if let Some(text_decl) = &self.text_decl {
+            text_decl.write(writer).await?;
+        }
+        self.content.write(writer).await?;
+        Ok(())
+    }
+}
+
+/// [80]   	EncodingDecl	   ::=   	S 'encoding' Eq ('"' EncName '"' | "'" EncName
+impl<'s> Composer<'s> for EncodingDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        S.write(writer).await?;
+        writer.write_all("encoding".as_bytes()).await?;
+        Eq.write(writer).await?;
+        writer.write_all("\"".as_bytes()).await?;
+        self.0.write(writer).await?;
+        writer.write_all("\"".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [81]   	EncName	   ::=   	[A-Za-z] ([A-Za-z0-9._] | '-')*
+impl<'s> Composer<'s> for EncName<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all(self.0.as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [82]   	NotationDecl	   ::=   	'<!NOTATION' S Name S (ExternalID | PublicID) S? '>'
+impl<'s> Composer<'s> for NotationDecl<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("<!NOTATION".as_bytes()).await?;
+        S.write(writer).await?;
+        self.name.write(writer).await?;
+        S.write(writer).await?;
+        match &self.id {
+            NotationDeclID::External(external_id) => external_id.write(writer).await?,
+            NotationDeclID::Public(public_id) => public_id.write(writer).await?,
+        }
+        writer.write_all(">".as_bytes()).await?;
+        Ok(())
+    }
+}
+
+/// [83]   	PublicID	   ::=   	'PUBLIC' S PubidLiteral
+impl<'s> Composer<'s> for PublicID<'s> {
+    async fn write<W>(&self, writer: &mut W) -> io::Result<()>
+    where
+        W: Unpin + AsyncWrite,
+    {
+        writer.write_all("PUBLIC".as_bytes()).await?;
+        S.write(writer).await?;
+        self.0.write(writer).await?;
+        Ok(())
     }
 }
diff --git a/src/xml/mod.rs b/src/xml/mod.rs
index 8df2f41..f072fde 100644
--- a/src/xml/mod.rs
+++ b/src/xml/mod.rs
@@ -345,6 +345,7 @@ pub struct Elementdecl<'s> {
 }
 
 // TODO: casings???
+// TODO: wtf does that todo mean?
 /// [46]   	contentspec	   ::=   	'EMPTY' | 'ANY' | Mixed | children
 #[derive(Clone, Debug)]
 pub enum Contentspec<'s> {
@@ -469,7 +470,8 @@ pub struct Enumeration<'s>(Vec<Nmtoken<'s>>);
 pub enum DefaultDecl<'s> {
     Required,
     Implied,
-    Fixed(AttValue<'s>),
+    /// if bool == true, attribute MUST always have default value
+    Fixed(bool, AttValue<'s>),
 }
 
 /// [61]   	conditionalSect	   ::=   	includeSect | ignoreSect
@@ -544,7 +546,7 @@ pub enum EntityDef<'s> {
     EntityValue(EntityValue<'s>),
     ExternalID {
         external_id: ExternalID<'s>,
-        ndata_decl: Option<NDataDecl<'s>>,
+        n_data_decl: Option<NDataDecl<'s>>,
     },
 }
 
@@ -583,8 +585,9 @@ pub struct ExtParsedEnt<'s> {
     content: Content<'s>,
 }
 
-/// [80]   	EncodingDecl	   ::=   	S 'encoding' Eq ('"' EncName '"' | "'" EncName
+/// [80]   	EncodingDecl	   ::=   	S 'encoding' Eq ('"' EncName '"' | "'" EncName "'" )
 #[derive(Debug)]
+// TODO?: select quote version
 pub struct EncodingDecl<'s>(EncName<'s>);
 
 /// [81]   	EncName	   ::=   	[A-Za-z] ([A-Za-z0-9._] | '-')*
diff --git a/src/xml/parsers.rs b/src/xml/parsers.rs
index 93ff5b1..232ebd0 100644
--- a/src/xml/parsers.rs
+++ b/src/xml/parsers.rs
@@ -1082,8 +1082,8 @@ impl<'s> Parser<'s, DefaultDecl<'s>> for DefaultDecl<'s> {
             value(DefaultDecl::Required, tag("#REQUIRED")),
             value(DefaultDecl::Implied, tag("#IMPLIED")),
             map(
-                preceded(opt(pair(tag("#FIXED"), S::parse)), AttValue::parse),
-                |att_value| DefaultDecl::Fixed(att_value),
+                pair(opt(pair(tag("#FIXED"), S::parse)), AttValue::parse),
+                |(must, att_value)| DefaultDecl::Fixed(must.is_some(), att_value),
             ),
         ))(input)
     }
@@ -1272,9 +1272,9 @@ impl<'s> Parser<'s, EntityDef<'s>> for EntityDef<'s> {
             }),
             map(
                 pair(ExternalID::parse, opt(NDataDecl::parse)),
-                |(external_id, ndata_decl)| EntityDef::ExternalID {
+                |(external_id, n_data_decl)| EntityDef::ExternalID {
                     external_id,
-                    ndata_decl,
+                    n_data_decl,
                 },
             ),
         ))(input)