OCLC has a new announcement on their treatment on ISBN-13 numbers. It is not the same as the current cataloging guidelines. "For original records, OCLC libraries should input ISBN-13 numbers into an EAN field (024, first indicator '3') rather than inputting into the ISBN field (020)." How does this impact searching, not only in OCLC but in the systems these records are downloaded into? What fields should a Z39.50 client search in an ISBN search? I'm very interrested in this topic since I'll be presenting on this at the Texas Library Association conference.