Recording the ISSN displayed on the serial is useful for searching and record matching on local systems, citation indexes, and full text databases.  The centers of the ISSN Network currently assign separate ISSN to paper and online versions of a serial; however, not all online versions have been assigned a separate ISSN by the appropriate center.  If separate ISSN have been assigned, sometimes ISSN for both the print and online versions are displayed on issues of the e-serial or in related pages on the serial's Web site.

When print and online format ISSN are given (sometimes clearly labeled "print" and "E-ISSN"), record the ISSN for online version in $a of the 022 and record the ISSN for the print in $y of the 022.  If the publisher appears to be printing the ISSN of the print instead of a separate ISSN for the online format, record the ISSN of the print in $y of the 022.  If unsure which format the ISSN is for, record it in $y.  If the serial does not print an ISSN but one format’s ISSN, or both are known, they may be placed in the appropriate subfields of the 022.

See also:

Module 31.  Remote Access Electronic Serials (Online Serials)