diff -r ab32922f139b -r ee659bca8955 src/HOL/SPARK/Manual/Reference.thy
--- a/src/HOL/SPARK/Manual/Reference.thy	Thu Oct 15 14:55:19 2020 +0200
+++ b/src/HOL/SPARK/Manual/Reference.thy	Sat Oct 17 18:56:36 2020 +0200
@@ -1,6 +1,6 @@
 (*<*)
 theory Reference
-imports "HOL-SPARK.SPARK"
+imports "HOL-SPARK.SPARK" "HOL-Word.Bits_Int"
 begin
 
 syntax (my_constrain output)