Repeatability of fields and subfields:
The MARC guidelines for each field and subfield indicate whether a field can be repeated within the same record or a subfield repeated within the same field.
Theoretically, all fields and subfields may be repeated. The nature of the data in the field, however, often precludes repetition. The repeatability (R) or nonrepeatability (NR) of each field and subfield is specified.
Field and subfield repeatability/nonrepeatability is sometimes indicated in written and on-line MARC documentation by the abbreviations R or NR following the description of each field and subfield in the appropriate MARC format.
See also: