1. Abiteboul, S., Hull, R., Vianu, V.: Foundations of Databases. Addison-Wesley, Reading-Massachusetts, 1995
2. Lect Notes Comput Sci;S. Abiteboul,1995
3. Abiteboul, S., Beeri, C.: On the power of languages for the manipulation of complex objects. INRIA research report 846 (1988). Abstract in Proc. International Workshop on Theory and Applications of Nested Relations and Complex Objects. Darmstadt (1987)
4. Lect Notes Comput Sci;S. Abiteboul,1995
5. Aczel, P.: Non-Well-Founded Sets. CSLI Lecture Notes. No 14 (1988)