Other:

Code z (008/12) indicates that the 1XX field contains an established heading for a series that does not fit any of the other defined types of series but for which series-type treatment is required (e.g., a serial for which only an occasional issue is analyzed).

Example:

008/12   z

008/16   a  [code indicating heading may be used as a series added entry]

130  #0  $aChinese studies in history