diff -r 1e31ddcab458 -r 4c275405faae src/Doc/Eisbach/Preface.thy
--- a/src/Doc/Eisbach/Preface.thy	Sun Jan 15 16:28:03 2023 +0100
+++ b/src/Doc/Eisbach/Preface.thy	Sun Jan 15 18:30:18 2023 +0100
@@ -6,7 +6,7 @@
 
 text \<open>
   \<^emph>\<open>Eisbach\<close> is a collection of tools which form the basis for defining new
-  proof methods in Isabelle/Isar~@{cite "Wenzel-PhD"}. It can be thought of as
+  proof methods in Isabelle/Isar~\<^cite>\<open>"Wenzel-PhD"\<close>. It can be thought of as
   a ``proof method language'', but is more precisely an infrastructure for
   defining new proof methods out of existing ones.