853-855 Subfield $w - Frequency:

Subfield $w contains a one-character alphabetic code or a number that indicates the publication frequency of the item.  Subfield $w is not related to a specific caption.  It is input following the last Chronology caption used.  Specific publishing pattern information is contained in subfield $y (Regularity pattern), including exceptions to the frequency coded in this subfield.  Subfield $p is also used when both a frequency code and number of pieces per issuance need to be recorded for multipart titles.

Codes:  A one-character alphabetic code is used for a publishing pattern that has a fundamental periodicity.

Example:

854  00  $81$a(year)$wa

853  20  $81$av.$bno.$u12$vr$i(year)$j(month)$wm$x11

Number:  A number is used to specify the number of issues per year when no codable periodicity exists.  Because subfield $w is variable in length, no leading zero is used for a singe-character number.

Example:

853  02  $81$a(year)$b(month)$w4$ypm03,06,08,12

863  30  $81.1$a2002-2003

863  41  $81.2$a2004$b03

[The bibliographic unit is published four times a year at irregular intervals.]

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