* Renamed idref attributes as appropriate (Element, RootElement, etc.)
* Changed the id attribute on <XSchema> to RootElement (type IDREF) and declared 
<XSchema> in the XML version (oops)
* Removed Choice as a direct child of Choice and Seq as a direct child of Seq
* Added general entities and notations
* Allowed <XSchema> to be empty (models an empty DTD)
* Changed <NotationValue> to be an empty element with a Notation attribute (type 
IDREF)
* Changed <EnumerationValue> to be an empty element with a Value attribute (type 
NMTOKEN)
* Changed the content model of Mixed from (ElementRef*) to (ElementRef+)
The URL is still the same:
http://www.informatik.tu-darmstadt.de/DVS1/staff/bourret/xschema.html
Tomorrow I'll try to hash out a list of differences (aside from naming) between 
John's and my DTDs.  This should allow us to raise issues and create a single 
DTD.
-- Ron Bourret