MARC21       657     Index Term--Function (R)
  Subfields: 
             $a   Function
             $v   Form subdivision [NEW]
             $x   General subdivision (R)
             $y   Chronological subdivision (R)
             $z   Geographic subdivision (R)
             $2   Source of term
             $6   Linkage

 Indic/etc.: 1st: Undefined; contains a blank (#)
             2nd: Source of term
             7 Source specified in subfield $2