440 Subfield $v - Volume number/sequential designation:
Subfield $v contains the volume number or other sequential designation that identifies the particular item in a series.
Examples:
440 #0 $aEnvironmental science research ;$vv. 4
440 #0 $aRussian titles for the specialist,$x0305-3741 ;$vno. 78
440 #0 $aRomanica Gothoburgensia,$x0080-3863 ;$v12, 16