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Trang - http://www.thaiopensource.com/relaxng/trang.html
A open source multi-format schema converter based on RELAX NG. Includes documentation and download. |
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XML Well-Formedness Checker and Validator - http://www.cogsci.ed.ac.uk/~richard/xml-check.html
Checks an XML document (specified by URL) for well-formedness and optionally DTD-based validity and namespace correctness. Outputs canonical XML. Runs over the web and can be downloaded. |
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Examplotron - http://examplotron.org/
Uses instance documents as a lightweight schema language; sample documents are marked up with the information needed to guide a validator. |
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XMLProbe - http://www.xmlprobe.com/
Automated data quality checking of XML content. |
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Comparative Analysis of Six XML Schema Languages - http://www.cobase.cs.ucla.edu/tech-docs/dongwon/ucla-200008.html
Paper by Dongwon Lee and Wesley W. Chu comparing XML DTD, XML Schema, XDR, SOX, Schematron, and DSD. |