Guidelines for Recording Holdings: Chronology
- Level 3 - Only the highest level of chronology data, the year, is recorded.
- Level 4 - All levels of chronology data are recorded.
Choice of Chronology Element
- More than one date: When more than one type of date is present on the publication, select the date from the following preferred dates, in this order:
Date of coverage
Date of publication
Date of copyright
Date of printing - Reprint dates: Do not use reprint dates. Any reprint information should appear in the bibliographic description.
- Multiple calendar schemes: When more than one calendar scheme is present on the publication, use the Gregorian date. When only a non-Gregorian date is present, use the non-Gregorian date as the primary chronology, followed by the converted Gregorian date in brackets.
Form of Chronology Data
- Year: Record the year portion of dates using Arabic numbers, in four-digit format.
- Year(s) span for single volume: If a single volume or part spans a noncalendar year or more than one year, a forward slash is used to separate the beginning and ending years.
1969/1970 (noncalendar year or biennial publication) 1980/1982 (triennial publication)
- Exact year unknown:: Use a question mark to fill the space of the missing digit. If the century or decade is not known, the year is not recorded.
198? 18?? not 1??? - Hierarchy: Record chronological designations from the highest to the lowest level, using a colon to separate each level. If day information is present, record it in conjunction with the month, not as a separate hierarchical level.
1996:May 12 not 1996:May:12 - Months, seasons, and days: Record months, seasons, and days in
the vernacular form appearing on the publication (romanized, if necessary). See list of Abbreviations: Names of Months.
- Chronology not present: If no chronology data is present on the item, none shall be supplied. However, if an item normally carries chronology and such data is omitted from a specific piece, it may be supplied.

