Anthony C. Klug Calculating Constraints on Relational Expressions. 260-290 TODS5/P260.PDF 1980 5 ACM Trans. Database Syst. 3 db/journals/tods/tods5.html#Klug80 http://doi.acm.org/10.1145/320613.320615 db/journals/tods/Klug80.html journals/tods/AhoBU79 journals/is/TsichritzisK78 conf/ifip/Armstrong74 conf/sigmod/BeeriFH77 journals/tods/Bernstein76 ... ... persons/Codd72 ... conf/vldb/SagivY78 ...