Added license information about the DocBook 5 RELAX NG schema.
diff --git a/LICENSE-DOCBOOK-RNG b/LICENSE-DOCBOOK-RNG
new file mode 100644
index 0000000..06c16fe
--- /dev/null
+++ b/LICENSE-DOCBOOK-RNG
@@ -0,0 +1,24 @@
+Copyright 1992-2008 HaL Computer Systems, Inc.,
+O'Reilly & Associates, Inc., ArborText, Inc., Fujitsu Software
+Corporation, Norman Walsh, Sun Microsystems, Inc., and the
+Organization for the Advancement of Structured Information
+Standards (OASIS).
+
+Release: $Id: docbook.rnc 7661 2008-02-06 13:52:59Z nwalsh $
+
+Permission to use, copy, modify and distribute the DocBook schema
+and its accompanying documentation for any purpose and without fee
+is hereby granted in perpetuity, provided that the above copyright
+notice and this paragraph appear in all copies. The copyright
+holders make no representation about the suitability of the schema
+for any purpose. It is provided "as is" without expressed or implied
+warranty.
+
+If you modify the DocBook schema in any way, label your schema as a
+variant of DocBook. See the reference documentation
+(http://docbook.org/tdg5/en/html/ch05.html#s-notdocbook)
+for more information.
+
+Please direct all questions, bug reports, or suggestions for changes
+to the docbook@lists.oasis-open.org mailing list. For more
+information, see http://www.oasis-open.org/docbook/.
\ No newline at end of file
diff --git a/NOTICE b/NOTICE
index cea738e..dfbb5d3 100644
--- a/NOTICE
+++ b/NOTICE
@@ -28,3 +28,12 @@
(https://creativecommons.org/licenses/by/4.0/).
=========================================================================
+
+This product includes the DocBook V5.0 RELAX NG schema, Copyright
+1992-2008 HaL Computer Systems, Inc., O'Reilly & Associates, Inc.,
+ArborText, Inc., Fujitsu Software Corporation, Norman Walsh, Sun
+Microsystems, Inc., and the Organization for the Advancement of
+Structured Information Standards (OASIS). See license details in the
+LICENSE-DOCBOOK-RNG file.
+
+=========================================================================
