Codes that identify subject categories. Subject category codes are taken from controlled lists of codes. You may repeat 072 for multiple subject category codes.
1st Indicator
Undefined. The first indicator is undefined and contains a blank ( ).
Undefined
2nd indicator
Code source. Identifies the subject category code.
Source specified in subfield ‡2. Indicates that the code source is specified in subfield ‡2 .
072
7
E5 ‡x .510 ‡2 mesh
Subfields
‡a Subject category code
The subject category code.
‡x Subject category code subdivision
A subdivision of the code in subfield ‡a .
‡2 Source
The source of the subject category. Use subfield ‡2 if the 2nd indicator value is 7. See MARC Code Lists for Relators, Sources, Description Conventions (
http://lcweb.loc.gov/marc/relators).