diff --git a/Citadelle/examples/C_Model_init.thy b/Citadelle/examples/C_Model_init.thy
index b39139d1cd9a64878c4e6e33e28226d70e2e44a3..8282218d883be5affd69514fde67db5907cbc7bb 100644
--- a/Citadelle/examples/C_Model_init.thy
+++ b/Citadelle/examples/C_Model_init.thy
@@ -38,7 +38,7 @@
 
 theory C_Model_init
   imports Isabelle_Meta_Model.Printer_init
-          Citadelle.Old_Datatype
+          "HOL-Library.Old_Datatype"
 begin
 
 type_synonym int = integer