エドガー・F・コッド
↑ http://www.seas.upenn.edu/~zives/03f/cis550/codd.pdf
↑ doi:10.1145/362384.362685
↑ http://www.minet.uni-jena.de/dbis/lehre/ss2005/sem_dwh/lit/Cod93.pdf
↑ http://awards.acm.org/images/awards/140/articles/2485527.pdf