1. XML editor products, Available at http://www.perferctxml.com/soft.asp?cat=6
2. XML query working group, Available at http://www.w3.org/XML/Query
3. XUpdate - XML:DB Working draft, Available at http://www.xmldb.org/xupdate/xupdatewd.html
4. Alon, N., Milo, T., Neven, F., Suciu, D., Vianu, V.: XML with data values: Typechecking revisited. In: ACM Symposium on Principles of Database System (2001)
5. Bouchou, B., Duarte, D., Halfeld Ferrari Alves, M., Laurent, D.: Extending tree automata to model XML validation under element and attribute constraints. In: ICEIS (2003)