X30 Subfield $v - Form subdivision:

Subfield $v contains a form subdivision that designates a specific kind or genre of material as defined by the thesaurus being used.  Subfield $v is appropriate only when a form subject subdivision is added to a uniform title heading to form an extended subject heading.  Subfield $v is used for form terms when they function as indicated above; the terms are coded in subfield $x if they function as general subdivisions.

Examples:

130  #0  $aGawain and the Grene Knight$vBibliography

130  #0  $aNew York times (New York, N.Y. : 1857)$vIndexes

130  #0  $aBeowulf$xLanguage$vGlossaries, etc.

130  #0  $aBible.$pN.T.$vInterlinear translations