1. Minimal-Maximal Time Cause-Effect Structures
2. Codd E.F. (1969) Derivability, redundancy and consistency of relations stored in large data banks. IBM research report RJ599. August.
3. Dong J., Parsaei, H., and Kumar, A. (1995). Intelligent Feature Extraction for Concurrent Design and Manufacturing, H. Parsaei (ed), Prentice Hall. London.