Normative references are references to external documents or resources to which
        implementers of DITA must comply.
        
            
                - [Namespaces in XML 1.0]
 
                - T. Bray, D. Hollander, A. Layman, R. Tobin, and H. S. Thompson, editors,
                        Namespaces in XML 1.0 (Third Edition), http://www.w3.org/TR/2009/REC-xml-names-20091208/, W3C
                    Recommendation, 8 December 2009.
 
            
            
                - [Namespaces in XML 1.1]
 
                -  T. Bray, D. Hollander, A. Layman, and R. Tobin, editors, Namespaces in
                        XML 1.1 (Second Edition), http://www.w3.org/TR/2006/REC-xml-names11-20060816/, W3C
                    Recommendation, 16 August 2006
 
            
            
                - [RFC 2119]
 
                - S. Bradner, Key words for use in RFCs to Indicate Requirement
                        Levels, http://www.ietf.org/rfc/rfc2119.txt, IETF RFC 2119, March 1997.
 
            
            
                - [RFC 3986]
 
                - T. Berners-Lee, R. Fielding, and L. Masinter, Uniform Resource Identifiers
                        (URI): Generic Syntax, http://tools.ietf.org/html/rfc3986, IETF RFC 3986, January
                    2005.
 
                
            
            
                -  [XML 1.0]
 
                - T. Bray, J. Paoli, C. M. Sperberg-McQueen, E. Maler, and F. Yergeau, editors,
                        Extensible Markup Language (XML) 1.0 (Fifth Edition), http://www.w3.org/TR/REC-xml/, W3C Recommendation, 26 November
                    2008.
 
                -  
 
            
            
                - [XML 1.1]
 
                - T. Bray, J. Paoli, C.M. Sperberg-McQueen, E. Maler, F.Yergeau, and J. Cowan,
                    editors, Extensible Markup Language (XML) 1.1 (Second
                        Edition),http://www.w3.org/TR/2006/REC-xml11-20060816/, W3C
                    Recommendation, 16 August 2006, edited in place 29 September 2006.
 
            
            
                - [XSD 1.0 Structures]
 
                - H. S. Thompson, D. Beech, M. Maloney, and N. Mendelsohn, editors, XML
                        Schema Part 1: Structures Second Edition, http://www.w3.org/TR/xmlschema-1/, W3C Recommendation, 28 October
                    2004.
 
            
            
                - [XSD 1.0 Datatypes]
 
                -  P. V. Biron and A. Malhotra, editors, XML Schema Part 2: Datatypes Second
                        Edition, http://www.w3.org/TR/xmlschema-2/, W3C Recommendation, 28 October
                    2004.