I'm new to EAD and am trying to understand the differences between
documents that validate using the DTD and the XSD schema.

I used dtd2schema.xsl ( to
transform a DTD-valid document into an XSD schema-valid document.  I
have a question about one of the changes it made.

Before transformation (original DTD-valid EAD):
<ref target="ref01">This</ref> is an internal link.

After transformation using dtd2schema:
<ref xlink:type="simple" target="ref01" xlink:href="">This</ref> is an
internal link.

Why are the xlink:type="simple" and xlink:href="" attributes added?
Schema validation doesn't fail if I remove them.  Are either of them
necessary or desirable?  I understand why you'd see these if you had
linktype and href attributes in your original EAD.
Also, when would you use the href attribute on a ref element instead of
a target attribute?    

Thanks very much for any help in advance!

Katie Dunn
Technology & Metadata Librarian
Rensselaer Polytechnic Institute
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