Code 680 - Library of Congress Classification
Optional, repeatable Indicators not defined
Subfields: a - LCC Number - single or beginning of a range (NR) b - LCC Number - end of a range (NR) c - Explanatory terms (R)
Code 686 - Other Classification Numbers
Optional, repeatable Indicators not defined
Subfields: a - Class number, single or beginning of a range (NR) b - Class number, end of a range (NR) c - Explanatory terms (R) 2 - Subject system code (NR)