1. Deformation von t-Normen, ihre Symmetrien und Symmetriebrechungen;Demant,1994
2. Generalized t-conorms and closure operators;Drossos,1996
3. Compact semigroups irreducibly connected between two idempotents;Faucett,1955
4. Fibred triangular norms;Jenei;Fuzzy Sets and Systems,1999
5. Additive generators of t-norms which are not necessarily continuous;Klement,1996