--- a/emacs.rst	Wed Nov 14 10:03:42 2012 +0200
+++ b/emacs.rst	Sat Nov 17 21:28:18 2012 +0200
@@ -64,6 +64,7 @@
 See value of variable ``load-history`` (by C-h v load-history RET)::
 
   (symbol-file 'c-mode)
+  (find-lisp-object-file-name 'c-mode (symbol-function 'c-mode))
 
 Using edebug.
 -------------