658 INDEX TERM--CURRICULUM OBJECTIVE (R)Indicators - Both undefined; each contains a blank (^)Subfield Codes $a Main curriculum objective (NR) $b Subordinate curriculum objective (R) $c Curriculum code (NR) $d Correlation factor (NR) $2 Source of term (NR) $6 Linkage (NR) $8 Field link and sequence number (R)