XML Signature - slide "Comments Resulting from Schema"

Will want to structure it such that we can use these specifications
inline instead of the DTD
Can't have types be "or'd" subtypes, consequently keep location tag such
that:
<ObjectReference URI="http://...">
<ObjectReference IDREF="..."

or (depending on whichever we choose)

<Location URI="http://...">
<Location IDREF="...">

treat DigestMethod and others the similarly

<DigestMethod URI="http://...."
...
<Type MIME="mime-type/...">
<Type URI="urn:...">
<Type URI="http://..."
How to associate a prefix (that is associated with a namespace) when used in an attribute value?
<Signature xmlns="http://www.w3.org/1999/10/signature-core"
xmlns:nist="http://www.w3.org/1999/sig-core/nist>
...
<Algorithm URI="nist:sha1">
</Signature>