> > 2) As John suggests, expand the legal elements beneath an XSchema element.  
In
> >  particular, add AttDef, Choice, Sequence, Mixed, and Ref to the XSchema
> > element.  (NotationType and EnumerationType no longer exist.  I have added 
Ref
> > to John's list.)
> 
> My only criticism: I don't think Ref belongs here, simply because Refs
> don't have any content themselves: they are just pointers, so it seems
> useless, over-complicated, and confusing in XSchema to have pointers
> to pointers.
But Ref is a valid content model:
<ElementDecl Name="Section">
   <Ref Element="Paragraph" Frequency="OneOrMore"/>
</ElementDecl>
(i.e. <!ELEMENT Section (Paragraph+)>  )
If I want to be able to store more complex content models in an XSchema element 
(for reference from other XSchemas), why can't I store this one?
-- Ron Bourret