1. TRA: a model for a temporal relational algebra;Lorentzos,1987
2. information modeling in the context of system development;Bubenko,1980
3. Logic as a database language;Kowalski,1984
4. On an algebra for historical relational databases: two views;Clifford,1985
5. The historical relational data model (HRDM) and algebra based on lifespans;Clifford,1986