diff --git a/4.1.2-xml/docbook.cat b/4.1.2-xml/docbook.cat
index c24e5df..baa695c 100644
--- a/4.1.2-xml/docbook.cat
+++ b/4.1.2-xml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"
+       "docbookx.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" "docbookx.dtd"
diff --git a/4.2-xml/docbook.cat b/4.2-xml/docbook.cat
index 5fa6524..c077e38 100644
--- a/4.2-xml/docbook.cat
+++ b/4.2-xml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+       "docbookx.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
diff --git a/4.3-sgml/docbook.cat b/4.3-sgml/docbook.cat
index 601a6ab..8cff5bd 100644
--- a/4.3-sgml/docbook.cat
+++ b/4.3-sgml/docbook.cat
@@ -17,6 +17,13 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/sgml/4.3/docbook.dtd"
+       "docbook.dtd"
+
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook V4.3//EN"
diff --git a/4.3-xml/docbook.cat b/4.3-xml/docbook.cat
index 05dee55..a138e91 100644
--- a/4.3-xml/docbook.cat
+++ b/4.3-xml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd"
+       "docbookx.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
diff --git a/4.4-sgml/docbook.cat b/4.4-sgml/docbook.cat
index a95bdb5..8f1c6f9 100644
--- a/4.4-sgml/docbook.cat
+++ b/4.4-sgml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/sgml/4.4/docbook.dtd"
+       "docbook.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook V4.4//EN"
diff --git a/4.4-xml/docbook.cat b/4.4-xml/docbook.cat
index 8c6fb19..cc1e0bc 100644
--- a/4.4-xml/docbook.cat
+++ b/4.4-xml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd"
+       "docbookx.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
diff --git a/4.5-sgml/docbook.cat b/4.5-sgml/docbook.cat
index 9d12fc3..1952d58 100644
--- a/4.5-sgml/docbook.cat
+++ b/4.5-sgml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/sgml/4.5/docbook.dtd"
+       "docbook.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
diff --git a/4.5-xml/docbook.cat b/4.5-xml/docbook.cat
index 25ac4df..25260d2 100644
--- a/4.5-xml/docbook.cat
+++ b/4.5-xml/docbook.cat
@@ -17,6 +17,12 @@
   --
 
   -- ...................................................................... --
+  -- SYSTEM rewrite of web URL .............. ............................. --
+
+SYSTEM "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"
+       "docbookx.dtd"
+
+  -- ...................................................................... --
   -- DocBook driver file .................................................. --
 
 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"