diff --git a/README.org b/README.org
index a4fe474..5aca2c5 100644
--- a/README.org
+++ b/README.org
@@ -2251,7 +2251,7 @@ non-interactive =org-element= functions to an =Emacs-lisp= buffer.
 :CUSTOM_ID: sec:programming
 :END:
 
-** Common Lisp programming
+** [[https://dept-info.labri.fr/~strandh/Teaching/PFS/Common/Strandh-Tutorial/Dir-symbolic.html][Common Lisp programming]]
 :PROPERTIES:
 :CUSTOM_ID: sec:common-lisp-programming
 :END: