https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=28491 --- Comment #25 from Heather <heather_hernandez@nps.gov> --- My understanding of the use of $z in many fields, including the 035, is the same as Katrin's. A number *that is still valid* in use in another system can't be placed in a $z, and it hasn't been canceled in that other system. It is used exactly in that way in WorldCat--when records are merged, the ID numbers of the subordinated & replaced records are placed in a $z of an 035. A $z is also used in a similar way in bib records in the 020 ISBN field, for example, if a lot of books have a misprinted and incorrect ISBN number, it will be placed in a $z with the correct number in a $a. But some people may still be seeing and using the incorrect number, thus its presence in the record in the $z. So I think, too, that other system's valid ID numbers should be in a $a in 035s. -- You are receiving this mail because: You are watching all bug changes.