diff --git a/chapter05/bison.xml b/chapter05/bison.xml
deleted file mode 100644
index 362aa9d26..000000000
--- a/chapter05/bison.xml
+++ /dev/null
@@ -1,65 +0,0 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
-<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
-  "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
-  <!ENTITY % general-entities SYSTEM "../general.ent">
-  %general-entities;
-]>
-
-<sect1 id="ch-tools-bison" role="wrap">
-  <?dbhtml filename="bison.html"?>
-
-  <title>Bison-&bison-version;</title>
-
-  <indexterm zone="ch-tools-bison">
-    <primary sortas="a-Bison">Bison</primary>
-    <secondary>tools</secondary>
-  </indexterm>
-
-  <sect2 role="package">
-    <title/>
-
-    <xi:include xmlns:xi="http://www.w3.org/2003/XInclude"
-    href="../chapter06/bison.xml"
-    xpointer="xpointer(/sect1/sect2[1]/para[1])"/>
-
-    <segmentedlist>
-      <segtitle>&buildtime;</segtitle>
-      <segtitle>&diskspace;</segtitle>
-
-      <seglistitem>
-        <seg>0.6 SBU</seg>
-        <seg>10.0 MB</seg>
-      </seglistitem>
-    </segmentedlist>
-
-  </sect2>
-
-  <sect2 role="installation">
-    <title>Installation of Bison</title>
-
-    <para>Prepare Bison for compilation:</para>
-
-<screen><userinput>./configure --prefix=/tools</userinput></screen>
-
-    <para>Compile the package:</para>
-
-<screen><userinput>make</userinput></screen>
-
-    <para>To test the results, issue:
-    <userinput>make check</userinput>.</para>
-
-    <para>Install the package:</para>
-
-<screen><userinput>make install</userinput></screen>
-
-  </sect2>
-
-  <sect2 role="content">
-    <title/>
-
-    <para>Details on this package are located in
-    <xref linkend="contents-bison" role="."/></para>
-
-  </sect2>
-
-</sect1>
diff --git a/chapter05/flex.xml b/chapter05/flex.xml
deleted file mode 100644
index 9015fd129..000000000
--- a/chapter05/flex.xml
+++ /dev/null
@@ -1,77 +0,0 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
-<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
-  "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
-  <!ENTITY % general-entities SYSTEM "../general.ent">
-  %general-entities;
-]>
-
-<sect1 id="ch-tools-flex" role="wrap">
-  <?dbhtml filename="flex.html"?>
-
-  <title>Flex-&flex-version;</title>
-
-  <indexterm zone="ch-tools-flex">
-    <primary sortas="a-Flex">Flex</primary>
-    <secondary>tools</secondary>
-  </indexterm>
-
-  <sect2 role="package">
-    <title/>
-
-    <xi:include xmlns:xi="http://www.w3.org/2003/XInclude"
-    href="../chapter06/flex.xml"
-    xpointer="xpointer(/sect1/sect2[1]/para[1])"/>
-
-    <segmentedlist>
-      <segtitle>&buildtime;</segtitle>
-      <segtitle>&diskspace;</segtitle>
-
-      <seglistitem>
-        <seg>0.6 SBU</seg>
-        <seg>22.5 MB</seg>
-      </seglistitem>
-    </segmentedlist>
-
-  </sect2>
-
-  <sect2 role="installation">
-    <title>Installation of Flex</title>
-
-    <para>Flex contains several known bugs. These can be fixed with the
-    following patch:</para>
-
-<screen><userinput>patch -Np1 -i ../&flex-fixes-patch;</userinput></screen>
-
-    <para>The GNU autotools will detect that the Flex source code has been
-    modified by the previous patch and tries to update the man page
-    accordingly.  This does not work on many systems, and the default page is
-    fine, so make sure it does not get regenerated:</para>
-
-<screen><userinput>touch doc/flex.1</userinput></screen>
-
-    <para>Now prepare Flex for compilation:</para>
-
-<screen><userinput>./configure --prefix=/tools</userinput></screen>
-
-    <para>Compile the package:</para>
-
-<screen><userinput>make</userinput></screen>
-
-    <para>To test the results, issue:
-    <userinput>make check</userinput>.</para>
-
-    <para>Install the package:</para>
-
-<screen><userinput>make install</userinput></screen>
-
-  </sect2>
-
-  <sect2 role="content">
-    <title/>
-
-    <para>Details on this package are located in
-    <xref linkend="contents-flex" role="."/></para>
-
-  </sect2>
-
-</sect1>