Books in Series
Years: 4 editions, 1977-1985
Series were extracted from the Library of Congress's National Union Catalog and MARC files, Bowker's Books in Print and Out-of-Print files, PTLA series listings, publisher materials, the ABPR database, and Irregular Series and Annuals. Not as useful for my purposes, as what I'm considering as a series is really more of an imprint in some cases, and the Bowker definition is much more limited.
Books in Series (1977): covered only series from 1966
Books in Series in the United States (2nd ed., 1977): date no longer a criterion for inclusion
Books in Series, 3rd ed. (1980)
Books in Series, 1876-1949 (1982)
Books in Series, 4th. ed. (6 vols., 1985)