External File Format Links

• OASIS OpenDocument Home Page, contains the specification (in OpenOffice.org format and in PDF), as well as the RelaxNG schemas
• OpenOffice's File Format Site
• W3C (XHTML, CSS, XPath, XSL, SVG...)
• RelaxNG reference

Tutorials

• DTD Tutorial
• OASIS OpenDocument Essentials

Overviews

• A survey of XML standards

Tools

• XML diffmerge
• XML treediff
• Jing (Java tool for validating files against a RelaxNG schema)

Other

• OpenFormula - Early draft of a standard for representing formulas in spreadsheets and word processors - might be interesting.