To learn more about XML element declarations, see the following URL:
http://www.w3.org/TR/2004/REC-xml-20040204/#elemdecls
WebLogic Workshop uses XML Schemas (and not DTDs) for the validation of XML. To learn more about XML element type declarations with XML Schemas, see the following URL:
http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#cElement_Declarations