MARC21       008s'31  Index availability [obs.]
     Values: 
              #   No index published [obs.]
              a   Each issue contains index to its own contents (no volume index),
                  loose [obs.]
              b   In last issue of volume, loose, separately paged [obs.]
              c   In last issue of volume, loose, unpaged [obs.]
              d   In last issue of volume, attached [obs.]
              e   In first issue of next volume, loose, separately paged [obs.]
              f   In first issue of next volume, loose, unpaged [obs.]
              g   In first issue of next volume, attached [obs.]
              h   Published separately, free, automatically sent [obs.]
              i   Published separately, free, upon request [obs.]
              j   Published separately, bound from publisher, free, automatically
                  sent [obs.]
              k   Published separately, bound from publisher, free, upon request
[obs.]
              l   Received separately, bound from publisher [obs.]
              m   Supplement or subseries, indexed in parent journal index [obs.]
              u   Unknown [obs.]
              z   Other index availability [obs.]