534 Subfield $p - Introductory phrase:

Subfield $p contains a phrase that introduces the citation of the original version. This subfield must always be present.

Examples:

534 ##$pOriginally published:$cNew York : Garland, 1987.

534 ##$pOriginal version:$c[S.l. : s.n., 1832?] (New York : Mesier's Lith.).