Conceptual Relations between Databases Transformed under Join and Projection.

Giorgio Ausiello Carlo Batini Marina Moscarini Conceptual Relations between Databases Transformed under Join and Projection. 123-136 1980 conf/mfcs/1980 MFCS db/conf/mfcs/mfcs80.html#AusielloBM80 http://dx.doi.org/10.1007/BFb0022499