diff --git a/lib/layouts/theorems-ams-bytype.inc b/lib/layouts/theorems-ams-bytype.inc
index 28df746f4e..c3a95386be 100644
--- a/lib/layouts/theorems-ams-bytype.inc
+++ b/lib/layouts/theorems-ams-bytype.inc
@@ -374,3 +374,4 @@ Style Claim
 End
 
 Input theorems-case.inc
+Input theorems-refprefix.inc
diff --git a/lib/layouts/theorems-ams-chap-bytype.inc b/lib/layouts/theorems-ams-chap-bytype.inc
index c24d92f01d..b779cc2597 100644
--- a/lib/layouts/theorems-ams-chap-bytype.inc
+++ b/lib/layouts/theorems-ams-chap-bytype.inc
@@ -469,3 +469,4 @@ End
 
 
 Input theorems-case.inc
+Input theorems-refprefix.inc