1. R. Balbes and P. Dwinger, Distributive Lattices, University of Missouri Press, Columbia, Mo., 1974.
2. G. Birkhoff, Lattice Theory, 3rd Ed., American Mathematical Society, Providence, R. I., 1967.
3. L. Borkowski (Editor), Selected Works of J. ?ukasiewicz, North-Holland, Amsterdam, 1970.
4. R. Cignoli, Moisil algebras, Notas de Lógica Matemática No 27, Universidad Nacional del Sur, Bahía Blanca, 1970.
5. R. Cignoli, Some algebraic aspects of many-valued logics. In: A. I. Arruda, N. C. A. da Costa and A. M. Sette (editors), Proceedings of the Third Brazilian Conference on Mathematical Logic, Sociedade Brasileira de Lógica, São Paulo, 1980, pp. 49?68.