db/journals/jacm/McCuneH89.html William McCune Lawrence J. Henschen Maintaining state constraints in relational databases: a proof theoretic basis. 46-68 1989 36 J. ACM 1 http://doi.acm.org/10.1145/58562.59302 db/journals/jacm/jacm36.html#McCuneH89 JACM/36/P0046.pdf