1. S. Abiteboul and A. Bonner. Objects and views. In ACM International Conference on Management of Data (SIGMOD), pages 238–248, Denver, Colorado, USA, May 1991.
2. A. Albano, R. Bergamini, G. Ghelli, and R. Orsini. An object data model with roles. In International Conference on Very Large Databases, pages 39–52, 1993.
3. A. Albano, R. Bergamini, G. Ghelli, and R. Orsini. Fibonacci: a programming language for object databases. VLDB Journal, 4(3):403–444, July 95.
4. John Boyland and Giuseppe Castagna. Type-safe compilation of covariant specialization: a practical case. In ECOOP'96, number 1008 in Lecture Notes in Computer Science, pages 3–25. Springer, 1996.
5. V. Benzaken and A. Doucet. Thémis: a database programming language with integrity constraints. In Shasha Beeri, Ohori, editor, Proceedings of the 4th International Workshop on Database Programming Languages, Workshop in Computing, pages 243–262, New York City, USA, September 1993. Springer-Verlag.