src/HOL/Hahn_Banach/Hahn_Banach.thy

--- a/src/HOL/Hahn_Banach/Hahn_Banach.thy	Tue Oct 07 22:54:49 2014 +0200
+++ b/src/HOL/Hahn_Banach/Hahn_Banach.thy	Tue Oct 07 23:12:08 2014 +0200
@@ -10,7 +10,7 @@
 
 text {*
   We present the proof of two different versions of the Hahn-Banach
-  Theorem, closely following \cite[\S36]{Heuser:1986}.
+  Theorem, closely following @{cite \<open>\S36\<close> "Heuser:1986"}.
 *}
 
 subsection {* The Hahn-Banach Theorem for vector spaces *}