X00 Subfield $n - Number of part/section of a work:

Subfield $n contains a number designation for a part or section of a work used with a title in a name/title field. Numbering is defined as an indication of sequencing in any form (e.g., Part 1, Supplement A, Book two). For music, the serial, opus, or thematic index number, or a date used as a number, is contained in subfield $n.

Examples:

700 0#$aHomer.$tIliad.$nBook 16-19.$lEnglish.

700 12$aLucretius Carus, Titus.$tDe rerum natura.$nLiber 4.$f1987.

700 1#$aTolkien, J. R. R.$q(John Roland Reuel),$d1892-1973.$tLord of the rings.$n2,$pTwo towers.

[Part/section is both numbered and named.]

Multiple numberings for a part or section separated by a comma (which are usually alternative numberings) are contained in a single subfield $n.

Example:

700 12$aMendelssohn-Bartholdy, Felix,$d1809-1847.$tQuartets,$mpiano, strings,$nno. 2, op. 2,$rF minor.$f1972.

Multiple numberings for a part or section separated by a period (which are usually numberings of subparts) are contained in separate $n subfields.

Example:

700 12$aSchubert, Franz,$d1797-1828.$tImpromptus,$mpiano,$nD. 935.$nNo. 2.$f1985.

To return:

Use the key.