https://glossar.hs-augsburg.de/Spezial:Durchsuchen/:Codd,-20E.-20F.-20(1969):-20Derivability,-20Redundancy-20and-20Consistency-20of-20Relations-20Stored-20in-20Large-20Sata-20Banks
Codd, E. F. (1969): Derivability, Redundancy and Consistency of Relations Stored in Large Sata Banks