diff --git a/optlab/optlab.html b/optlab/optlab.html
index f62b2497849e7ede1aab3e156a00a63b2c186d95..889cd55ee00cb2963c734129100db497be6a8e96 100644
--- a/optlab/optlab.html
+++ b/optlab/optlab.html
@@ -74,6 +74,10 @@
   <a href="http://onelab.info/optlab/bin/optlab-1.0.0-Linux32.zip">Linux 32-bit</a> or
   <a href="http://onelab.info/optlab/bin/optlab-1.0.0-MacOSX.zip">MacOS</a>.
 </p>
+<p>
+  The OPTLAB source code is currently not publicly available: contact the
+  authors for further information.
+</p>
 
 <h2>References</h2>