654 SUBJECT ADDED ENTRY--FACETED TOPICAL TERMS (R)Indicators First Level of subject ^ No information provided 0 No level specified 1 Primary 2 Secondary Second Undefined; contains a blank (^)Subfield Codes $a Focus term (NR) $b Non-focus term (R) $c Facet/hierarchy designation (R) $v Form subdivision (R) $y Chronological subdivision (R) $z Geographic subdivision (R) $2 Source of heading or term (NR) $3 Material specified (NR) $6 Linkage (NR) $8 Field link and sequence number (R)