xISBN supplies ISBNs associated with individual intellectual works represented in the OCLC WorldCat database. Give it an ISBN, and it returns a list of associated ISBNs.

To be used by a program to return an XML document of all the associated ISBNs for a title.  Sort of like what I do for journal titles using SFX to return ISSNs. 

COinS (ContextObjects in Spans) is a simple, ad hoc community specification for publishing OpenURL references in HTML.

We should think about how to embed these in our pages...