Enric Trillas Susana Cubillo Elena Castiñeira Menger and Ovchinnikov on Indistinguishabilities, Revisited. 213-218 1999 7 International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems 3 http://dx.doi.org/10.1142/S0218488599000155 db/journals/ijufks/ijufks7.html#TrillasCC99