--- a/sh.rst	Sun Dec 11 12:02:51 2011 +0200
+++ b/sh.rst	Sun Dec 11 12:03:15 2011 +0200
@@ -17,6 +17,8 @@
   http://code.dogmap.org/lintsh/
                 lintsh is a Bourne shell that optionally warns about suspicious
                 or nonportable constructs
+  http://www.gnu.org/software/autoconf/manual/html_node/Portable-Shell.html
+                Portable Shell Programming
 
 Kill processes after timeout.
 =============================