Theoretically, all fields and subfields may be repeated.  The nature of the data, however, often precludes repetition.  For example, a bibliographic, authority, classification, or community information format record may contain only one 1XX field; a field 100 may contain only one subfield $a (Personal name) but may contain more than one subfield $c (Titles and other words associated with a name).

The repeatability or nonrepeatability of each field and subfield is indicated by guidelines written in MARC documentation and in the Cataloger's Reference Shelf by the abbreviations R or NR following the description of each field and subfield in the five MARC formats.

R

is the abbreviation used to indicate that a field may be repeated within a MARC record or a subfield may be repeated within a particular field.

NR

is the abbreviation used to indicate that a field may NOT be repeated within a MARC record or that a subfield may NOT be repeated within a particular field.

To return:

A General Introduction to the MARC Format