I'm sure someone out there will have a good example for this one.  (If someone 
would like to adopt this section, even better.)  This will work; it's just not 
nearly up to the high standards I'd like to maintain throughout the 
specification.
I'm also not completely sure about the use of href in the system identifier. 
Is it appropriate?  If it refers to a helper application, it seems like a bad 
idea.
If ever there was a neighborhood in XML I hoped to avoid visiting, it's this 
one.  I'm one of those strange people who actually _likes_ MIME types and 
HTTP's odd habit of identifying the content it delivers and expecting 
applications to cope. But hey, I could start using my ISBNs - or are those the 
property of my publisher?  Hmmm.  Time to read the contracts.
On to namespaces...
Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer / Cookies
2.5 Notation Declarations
Notation declarations are made with XSC:Notation elements nested in the 
XSC:XSchema element.
<!ELEMENT XSC:Notation (Doc?, ((PubidLiteral, SystemLiteral?) | 
SystemLiteral))>
<!ATTLIST XSC:Notation 
      name NMTOKEN #REQUIRED>
<!ELEMENT XSC:PubidLiteral EMPTY>
<!ATTLIST XSC:PubidLiteral
	Pubid CDATA #REQUIRED>
<!ELEMENT XSC:SystemLiteral EMPTY>
<!ATTLIST XSC:Systemliteral
	href CDATA #REQUIRED>
Notations may include either a Public Identifier and an optional system 
literal, or just a system literal.