diff --git a/chapter06/udev.xml b/chapter06/udev.xml
index 0f1ae802e..104f26122 100644
--- a/chapter06/udev.xml
+++ b/chapter06/udev.xml
@@ -115,7 +115,7 @@ have created, or (not in LFS) the name of the renamed network interface.</para>
 <varlistentry id="etc-dev-d">
 <term><filename class="directory">/etc/dev.d</filename></term>
 <listitem> <indexterm zone="ch-system-udev etc-dev-d"><primary
-sortas="b-etc-dev-d">/etc/dev.d</primary></indexterm>
+sortas="e-etc-dev-d">/etc/dev.d</primary></indexterm>
 <para>directory is supposed to contain user-written handlers for device
 creation hotplug events.</para>
 </listitem></varlistentry>
@@ -123,7 +123,7 @@ creation hotplug events.</para>
 <varlistentry id="etc-udev">
 <term><filename class="directory">/etc/udev</filename></term>
 <listitem> <indexterm zone="ch-system-udev etc-udev"><primary
-sortas="b-etc-udev">/etc/udev</primary></indexterm>
+sortas="e-etc-udev">/etc/udev</primary></indexterm>
 <para>directory contains <command>udev</command> configuation files,
 device permissions and rules for device naming.</para>
 </listitem></varlistentry>