MARC21       006s'01  Frequency
     Values: 
              #   No determinable frequency
              a   Annual
              b   Bimonthly
              c   Semiweekly
              d   Daily
              e   Biweekly
              f   Semiannual
              g   Biennial
              h   Triennial
              i   Three times a week
              j   Three times a month
              m   Monthly
              q   Quarterly
              s   Semimonthly
              t   Three times a year
              u   Unknown
              w   Weekly
              z   Other