1. A summary of user experience with the SQL data sublanguage;Chamberlain,1980
2. Constructing queries from tokens;Motro,1986
3. An implementation of GEM — supporting a semantic data model on a relational back-end;Tsur,1984
4. Correcting user errors in SQL;Welty;International Journal of Man-Machine Studies,1985
5. Design and implementation of an extended entity-relationship data base management system (ECRINS/86);Junet,1987