diff --git a/pdf/remove_links.py b/pdf/remove_links.py
index 1dc54a4..9bb9f4c 100755
--- a/pdf/remove_links.py
+++ b/pdf/remove_links.py
@@ -9,6 +9,7 @@ from pathlib import Path
 MATCHES = {
     '<strong>Module <a href="#operator">operator</a> provides functions itemgetter() and mul() that offer the same functionality as <a href="#lambda">lambda</a> expressions above.</strong>': '<strong>Module \'operator\' (p. 31) provides functions itemgetter() and mul() that offer the same functionality as lambda expressions (p. 11) above.</strong>',
     '<strong>Adding <code class="python hljs"><span class="hljs-string">\'!r\'</span></code> before the colon converts object to string by calling its <a href="#class">repr()</a> method.</strong>': '<strong>Adding <code class="python hljs"><span class="hljs-string">\'!r\'</span></code> before the colon converts object to string by calling its repr() method (p. 14).</strong>',
+    '<strong>It can be any <a href="#callable">callable</a>, but is usually implemented as a function that returns a <a href="#closure">closure</a>.</strong>': '<strong>It can be any callable (p. 17), but is usually implemented as a function that returns a closure (p. 12).</strong>',
     '<strong>Default_factory can be any <a href="#callable">callable</a>.</strong>': '<strong>Default_factory can be any callable (p. 17).</strong>',
     '<strong>Sequence iterators returned by the <a href="#iterator">iter()</a> function, such as list_iterator and set_iterator.</strong>': '<strong>Sequence iterators returned by the iter() function, such as list_iterator and set_iterator (p.&nbsp;3).</strong>',
     '<strong>Objects returned by the <a href="#itertools">itertools</a> module, such as count, repeat and cycle.</strong>': '<strong>Objects returned by the itertools module, such as count, repeat and cycle (p. 3).</strong>',