diff --git a/Manuals/Common_content/Entities.ent b/Manuals/Common_content/Entities.ent
index 4eabe3b..a99e657 100644
--- a/Manuals/Common_content/Entities.ent
+++ b/Manuals/Common_content/Entities.ent
@@ -9,8 +9,6 @@
 <!-- Common document structure -->
 
 <!ENTITY preface                SYSTEM "Preface.docbook">
-<!ENTITY preface-overview       SYSTEM "Preface/overview.docbook">
-<!ENTITY preface-history        SYSTEM "Preface/history.docbook">
 <!ENTITY preface-docconvs       SYSTEM "Preface/docconvs.docbook">
 <!ENTITY preface-feedback       SYSTEM "Preface/feedback.docbook">