Ryohei Nakano Translation with Optimization from Relational Calculus to Relational Algebra Having Aggregate Functions. 518-557 TODS15/P518.PDF 1990 15 ACM Trans. Database Syst. 4 db/journals/tods/tods15.html#Nakano90 http://doi.acm.org/10.1145/99935.99943 conf/vldb/Bultzingsloewen87 journals/tse/CeriG85 persons/Codd72 journals/tods/Codd79 conf/adbt/Chang77 ... conf/vldb/Dayal87 conf/iwdm/DeWittGSJMS87 conf/sigmod/Freytag87 conf/sigmod/GraefeD87 conf/sigmod/HaasFLP89 ... conf/sigmod/JarkeK83 journals/csur/JarkeK84 conf/vldb/Kiessling85 journals/tods/Kim82 journals/jacm/Klug82 conf/iwdm/LelandR87 ... books/cs/Maier83 conf/iwdm/NakanoK87 journals/cacm/SmithC75 books/cs/Ullman82 journals/tods/Yao79