1. Felix, R.; Reddig, S.: „Qualitative Pattern Analysis for Industrial Quality Assurance“. Proceedings of the 2nd IEEE Conference on Fuzzy Systems Vol I. San Francisco, USA (March 28-April 1, 1993 ): 204–206.
2. Felix, R.: „Entscheidungen bei qualitativen Zielen“, Universität Dortmund, Fachbereich Informatik, Forschungsbericht Nr. 412, 1992
3. Felix, R.: „Multiple Attribute Decision Making based on Fuzzy Relationships between Objectives“, Proceedings of the 2nd International Conferenca on Fuzzy Logic and Neural Networks, Iizuka, Japan, 1992
4. Felix, R.: „Goal-oriented Selection of Alternatives Based on Fuzzy Sets“, IPMU Information Processing and Management of Uncertainty in Knowledge-based Systems, Paris, France, 1990
5. Zadeh, L.A.: „Similarity Relations and Fuzzy Orderings“, Yager, Ovchinnikov, Tong, Nguyen, FUZZY SETS AND APPLICATIONS, Selected Papers by L.A. Zadeh, Wiley-Interscience, 1987