diff --git a/doc/polymaking.bib b/doc/polymaking.bib
index 5849d22..4fe7ca0 100644
--- a/doc/polymaking.bib
+++ b/doc/polymaking.bib
@@ -18,5 +18,5 @@ @unpublished{math.CO/0507273
 @Misc{polymake,
   author = 	 "Ewgenij Gawrilow and Michael Joswig",
   title = 	 {polymake},
-  howpublished = {\URL{http://polymake.org/}}
+  howpublished = {\url{http://polymake.org/}}
 }