1. Anderson, A. R. andBelnap, N. D., Jr.,Entailment. Vol. 1, Princeton U.P., Princeton, 1975.
2. Anderson, A. R., Belnap, N. D. Jr. andDunn, J. M.,Entailment, Vol. 2, Princeton U.P., Princeton, 1992.
3. Andr�ka, H.,Representations of distributive lattice-ordered semigroups with binary relations, Algebra Universalis28 (1991), 12?25.
4. Birkhoff, G.,Lattice Theory, American Mathematical Society, Providence. Rhode Island, 1973.
5. Chin, L. andTarski, A.,Distributive and modular laws in the arithmetic of relation algebras. University of California Publications in Mathematics, new series, Vol. 1, no. 9 (1951), 341?384.