A Relational Model of Data for Large Shared Data Banks (Reprint).

E. F. Codd A Relational Model of Data for Large Shared Data Banks (Reprint). 64-69 1983 26 Commun. ACM 1 db/journals/cacm/cacm26.html#Codd83 http://doi.acm.org/10.1145/357980.358007