conf/sigmod/76 Patricia P. Griffiths Bradford W. Wade An Authorization Mechanism for a Relational Data Base System (Abstract). 51 1976 SIGMOD Conference db/conf/sigmod/sigmod76.html#GriffithsW76 http://doi.acm.org/10.1145/509383.509393 db/conf/sigmod/GriffithsW76.html SIGMOD76/P051.PDF