d daily once per day
i -------- three times per week
c semiweekly two times per week ('half of a week')
w weekly once per week
j -------- three times per month
e biweekly every two weeks
s semimonthly two times per month ('half of a month')
m monthly once per month
b bimonthly every two months
q quarterly four times per year
t -------- three times per year
f semiannual, *biannual two times per year ('half of a year')
a annual once per year
g biennial every two years
h triennial every three years
z -------- other frequencies (quadrennial - every four years, quinquennial - every five years, etc.)
k irregular known to be so (no determinable frequency)
u -------- unknown frequency

* sounds contradictory, but semiannual and biannual are used interchangeably


CONSER Editing Guide, 1994
ISDS Manual, 1983
MARC 21 Format for Bibliographic Data, 1999

3/2/00 PC