diff --git a/ext/nokogiri/xml_document.c b/ext/nokogiri/xml_document.c
index eb1a3b95630..19bb876b822 100644
--- a/ext/nokogiri/xml_document.c
+++ b/ext/nokogiri/xml_document.c
@@ -367,7 +367,7 @@ static VALUE new(int argc, VALUE *argv, VALUE klass)
  *
  *  For more information on why this probably is *not* a good thing in general,
  *  please direct your browser to
- *  http://tenderlovemaking.com/2009/04/23/namespaces-in-xml/
+ *  http://tenderlovemaking.com/2009/04/23/namespaces-in-xml.html
  */
 VALUE remove_namespaces_bang(VALUE self)
 {