diff -r dc311d55ad8f -r 6e1e8b5abbfa src/HOL/Predicate_Compile_Examples/Reg_Exp_Example.thy
--- a/src/HOL/Predicate_Compile_Examples/Reg_Exp_Example.thy	Fri Aug 12 17:49:02 2016 +0200
+++ b/src/HOL/Predicate_Compile_Examples/Reg_Exp_Example.thy	Fri Aug 12 17:53:55 2016 +0200
@@ -4,7 +4,7 @@
   "~~/src/HOL/Library/Code_Prolog"
 begin
 
-text \<open>An example from the experiments from SmallCheck (@{url "http://www.cs.york.ac.uk/fp/smallcheck/"})\<close>
+text \<open>An example from the experiments from SmallCheck (\<^url>\<open>http://www.cs.york.ac.uk/fp/smallcheck\<close>)\<close>
 text \<open>The example (original in Haskell) was imported with Haskabelle and
   manually slightly adapted.
 \<close>