1. Ehrenberg, A.S.: Repeat-Buying: Facts, Theory and Applications, 2nd edn. Charles Griffin & Company Ltd., London (1988)
2. Lecture Notes in Computer Science;A. Geyer-Schulz,2003
3. Geyer-Schulz, A., Neumann, A., Thede, A.: An architecture for behavior-based library recommender systems – integration and first experiences. Information Technology and Libraries 22 (2003)
4. Yang, Y.: An evaluation of statistical approaches to text categorization. Information Retrieval 1, 69–90 (1999)
5. Creecy, R.H., Masand, B.M., Smith, S.J., Waltz, D.L.: Trading mips and memory for knowledge engineering. Communications of the ACM 35, 48–64 (1992)