>Hmm, 2 ISBNs in 2nd place -- how many are situations of coupled >ISBN-10 and ISBN-13 pairs and how many are "distinct"? The >"instance" plot thickens. :-) Good observation! Thanks! Inadvertently creating two Instances of the same item, one with the 10 digit ISBN, and one with the 13 digit one, would be *very* frustrating. Hope you are reading this Kevin. Tain't so so simple is it? Mac __ __ J. McRee (Mac) Elrod ([log in to unmask]) {__ | / Special Libraries Cataloguing HTTP://www.slc.bc.ca/ ___} |__ \__________________________________________________________