1. S. Bairamian, Goal Search in Relational Databases, Thesis, California State niversity at Northridge, 1989.
2. W. Chu, Neighborhood and associative query answering, Journal of Intelligent Information Systems, 1 (1992), 355–382.
3. K. Engesser, Some connections between topological and Modal Logic, Mathematical Logic Quarterly, 41 (1995), 49–64.
4. T. Y. Lin, Neighborhood Systems and Relational Database. In: Proceedings of 1988 ACM Sixteen Annual Computer Science Conference, February 23–25, 1988, 725
5. T. Y. Lin, Neighborhood Systems and Approximation in Database and Knowledge Base Systems. In; Proceedings of the Fourth International Symposium on Methodologies of Intelligent Systems, Poster Session, October 12–15, 1989, pp. 75–86.