conf/sigmod/80 Hirotaka Sakai Entity-Relationship Approach to the Conceptual Schema Design. 1-8 1980 SIGMOD Conference db/conf/sigmod/sigmod80.html#Sakai80 SIGMOD80/P001.PDF http://doi.acm.org/10.1145/582250.582252 db/conf/sigmod/Sakai80.html ... journals/tods/Chen76 ... ... journals/tods/Delobel78 conf/er/Sakai79 journals/tods/Rissanen77 conf/er/ScheuermannSW79