commit 0e4c9a39789b6dbcd44b2e0d4a42b5885d3bddb2
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Sep 1 10:57:46 2022 +0100

    Replace stale link to the "An Introduction to GCC" book

diff --git a/htdocs/readings.html b/htdocs/readings.html
index 4269e9f0..5d1b78e8 100644
--- a/htdocs/readings.html
+++ b/htdocs/readings.html
@@ -22,8 +22,9 @@
 
 <ul>
 
-  <li><a href="http://www.network-theory.co.uk/gcc/intro/">An Introduction
-  to GCC</a> by Brian J. Gough.</li>
+  <li><a href="https://web.archive.org/web/20060106062936/http://www.network-theory.co.uk/gcc/intro/">An Introduction
+  to GCC</a> by Brian J. Gough
+  (<a href="https://archive.org/details/B-001-002-835/">e-book</a>).</li>
 
   <li><a href="https://en.wikibooks.org/wiki/GNU_C_Compiler_Internals">GNU C Compiler Internals (Wikibook)</a>, numerous contributors.</li>