1. Atkin, A.: Peirce’s theory of signs. In: Zalta, E.N. (ed.) The Stanford Encyclopedia of Philosophy, summer 2013 edn. (2013)
2. Bosnjak, I., Madarasz, R.: On some classes of good quotient relations. Novisad J. Math. 32(2), 131–140 (2002)
3. Cattaneo, G., Ciucci, D.: Algebras for rough sets and fuzzy logics. In: Transactions on Rough Sets 2 (LNCS 3100), pp. 208–252 (2004)
4. Chajda, I.: Ternary Deductive Systems. In: Pinus, A.G., Ponomaryov, K.N. (eds.) Algebra i Teoria Modelej 3, pp. 14–18. Novosibirsk STU (1998)
5. Chajda, I.: Generalized deductive systems in subregular varieties. Math. Bohemica 128(3), 319–324 (2003)