1. A review of some methods for ranking fuzzy subsets;Bortolan;Fuzzy Sets and Systems,1985
2. Fuzzy arithmetic and comparison of fuzzy numbers;Chang,1994
3. Metric spaces of fuzzy sets;Diamond;Fuzzy Sets and Systems,1990
4. P. Grzegorzewski and O. Hryniewicz, Testing statistical hypotheses in fuzzy environment, Working Papers of Systems Research Institute, Polish Academy of Sciences, WP-6-1995.
5. The expected value of a fuzzy number;Heilpern;Fuzzy Sets and Systems,1992