Thom has some more details about Worldcat Identities.

What is returned is really XML with a reference to an XSL stylesheet to transform the XML into the HTML displayed by the browser. [Outgoing: Links to WorldCat Identities]

He talks about how links from Worldcat work and also describes direct linking approaches ...

http://worldcat.org/identities/find?fullName=colm+toibin

http://worldcat.org/identities/lccn-n81-98944