MARC21       007s'09  Kind of disc, cylinder or tape
     Values: 
              a   Master tape
              b   Tape duplication master
              d   Disc master (negative)
              i   Instantaneous (recorded on the spot)
              m   Mass produced
              n   Not applicable
              r   Mother (positive)
              s   Stamper (negative)
              t   Test pressing
              u   Unknown
              z   Other