db/journals/jacm/BeeriDFS84.html Catriel Beeri Martin Dowd Ronald Fagin Richard Statman On the Structure of Armstrong Relations for Functional Dependencies. 30-46 1984 31 J. ACM 1 http://doi.acm.org/10.1145/2422.322414 db/journals/jacm/jacm31.html#BeeriDFS84 JACM/31/P0030.pdf