John L. Pfaltz William J. Berman Edgar M. Cagley Partial-Match Retrieval Using Indexed Descriptor Files. 522-528 1980 23 Commun. ACM 9 db/journals/cacm/cacm23.html#PfaltzBC80 db/journals/cacm/PfaltzBC80.html CACMs1/CACM23/P522.pdf