For Further Exploration
Articles
XML Conformance Update (validation), David Brownell
http://www.xml.com/pub/2000/05/10/conformance/conformance.html
XML.com: Being Too Generous, Leigh Dodds [discusses XML conformance in Internet Explorer 6]
http://www.xml.com/pub/a/2001/09/19/being-too-generous.html
To Validate or Not to Validate: Controversy
http://WDVL.Internet.com/Authoring/Languages/XML/DoingIt/ ValidationControversy.html
Resources
XML Checkers and Validation Services
http://WDVL.Internet.com/Software/XML/parsers.html#checking
XML.com: Search for Conformance
http://www.xml.com/search/index.ncsp?sp-q=Conformance&search=search
Software
XML Parsers at XMLSoftware
http://www.xmlsoftware.com/parsers/
XML Editors at XMLSoftware
http://www.xmlsoftware.com/editors/
W3C Specifications
Extensible Markup Language (XML) 1.0 [W3C XML Recommendation, Second Edition]
Well-Formed XML Documents
http://www.w3.org/TR/REC-xml#sec-well-formed
Validating and Non-Validating Processors
http://www.w3.org/TR/REC-xml#proc-types
XHTML 1.0: The Extensible HyperText Markup LanguageA Reformulation of HTML 4 in XML 1.0