diff --git a/man/colorhug-ccmx.sgml b/man/colorhug-ccmx.sgml
index e9ffde2..a330611 100644
--- a/man/colorhug-ccmx.sgml
+++ b/man/colorhug-ccmx.sgml
@@ -1,4 +1,6 @@
-<!doctype refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1/docbookx.dtd" [
   <!-- Please adjust the date whenever revising the manpage. -->
   <!ENTITY date        "<date>02 January,2012</date>">
   <!ENTITY package     "colorhug-ccmx">
diff --git a/man/colorhug-cmd.sgml b/man/colorhug-cmd.sgml
index 2358e05..837480d 100644
--- a/man/colorhug-cmd.sgml
+++ b/man/colorhug-cmd.sgml
@@ -1,4 +1,6 @@
-<!doctype refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1/docbookx.dtd" [
   <!-- Please adjust the date whenever revising the manpage. -->
   <!ENTITY date        "<date>07 September,2010</date>">
   <!ENTITY package     "colorhug-cmd">
diff --git a/man/colorhug-flash.sgml b/man/colorhug-flash.sgml
index 376251b..643f54c 100644
--- a/man/colorhug-flash.sgml
+++ b/man/colorhug-flash.sgml
@@ -1,4 +1,6 @@
-<!doctype refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1/docbookx.dtd" [
   <!-- Please adjust the date whenever revising the manpage. -->
   <!ENTITY date        "<date>07 September,2010</date>">
   <!ENTITY package     "colorhug-flash">