1. Berson, A., Smith, S.: Data Warehousing, Data Mining and OLAP. McGraw-Hill, New York (1997)
2. Bertino E., Martino L.: Object-Oriented Database Systems. Addison Wesley, Wokingham (1993)
3. Studies in Fuzziness and Soft Computing,2000
4. Bosc P., Kacprzyk J. (eds.): Fuzziness in Database Management Systems. Physica, Heidelberg (1995)
5. Cattell R. G.G.: Object Data Management—Object-Oriented and Extended Relational Database Systems. Addison Wesley, Reading (1994)