Extending the Data Base Relational Model to Capture More Meaning (Abstract).

conf/sigmod/79 E. F. Codd Extending the Data Base Relational Model to Capture More Meaning (Abstract). 161 1979 SIGMOD Conference db/conf/sigmod/sigmod79.html#Codd79 SIGMOD79/P161.PDF http://doi.acm.org/10.1145/582095.582122