Identifiers: ISSN, Invalid ISSN, Linking ISSN

ISSN, Invalid ISSN, Linking ISSN (rows 7, 8, 9)
Review the subfields carefully to determine ISSN Identifier Type

• 022 $a = [Valid] ISSN
• 022 $m $y $z = Invalid ISSN
• 022 $l = Linking ISSN

Each of the above subfields should be in a separate Instance ISSN field, even if they are in the same MARC 022 field.

022 $a2169-1665$l0040-781X$y0040-781X
Becomes

• [Valid] ISSN 2169-1665
• Linking ISSN 0040-781X
• Invalid ISSN 0040-781X