440 Subfield $x - International Standard Serial Number:

Subfield $x contains the International Standard Serial Number (ISSN) for a series title given in a series statement. The ISSN is an agency-assigned data element . ISSNs are assigned to serial publications (including series) by national centers under the auspices of the ISSN Network.

Example:

440 #0$aCentre of Asian Studies occasional papers and monographs,$x0378-2689 ;$vno. 57

Note: When an item contains an ISSN for the series but lacks a series title, the ISSN is recorded in a 500 General Note field.

Example:

500 ##$a"ISSN 0399-3388."

See also:

022 International Standard Serial Number