1. An Introduction to Database Systems, 4th ed., Vol. 1, Addison-Wesley, Reading, MA, 1986.
2. “A step towards the theory of fuzzy relational database design,” In Proceedings of IFSA'91 World Congress, Brussels, 1991, pp. 44–47.
3. “Fuzzy data modeling: Perspectives, problems and solutions,” In Introduction to the Basic Principles of Fuzzy Set Theory and Some of its Applications Ed., Communication & Cognition, Gent, Belgium, 1991, pp. 294–343.
4. , and , “Fuzzy functional dependency and its axiomatic system in a fuzzy relational data model,” In Proceedings of the International Conference on Information Processing and Management of Uncertainty (IPMU'92), Palma, Spain, 1992, pp. 313–316.
5. A general treatment of data redundancy in a fuzzy relational data model