1. Freyd, P., Scedrov, A.: Categories, Allegories, vol. 39. North-Holland Mathematical Library, Amsterdam (1990)
2. Furusawa, H.: Algebraic formalizations of fuzzy relations and their representation theorems. Ph.D.-thesis, Department of Informatics, Kyushu University, Japan (1998)
3. Furusawa, H., Kawahara, Y., Winter, M.: Dedekind categories with cutoff operators. Fuzzy Sets Syst. 173, 1–24 (2011)
4. Jónsson, B., Tarski, A.: Boolean algebras with operators, I, II. Amer. J. Math. 73, 891–939 (1951). 74, 127–162 (1952)
5. Kawahara, Y., Furusawa, H.: Crispness and representation theorems in dedekind categories. DOI-TR 143, Kyushu University (1997)