V. Gisin. On the symmetry of fuzzy sets. In Gaspar Mayor, Jaume Suñer, editors, Proceedings of the EUSFLAT-ESTYLF Joint Conference, Palma de Mallorca, Spain, September 22-25, 1999. pages 413-415, Universitat de les Illes Balears, Palma de Mallorca, Spain, 1999. [doi]
Abstract is missing.