1. A. R. Anderson and N. D. Belnap, Jr., Entailment, Vol. I, Princeton University Press, 1975.
2. W. J. Blok and D. Pigozzi, The deduction theorem in algebraic logic, manuscript.
3. J. M. Dunn, Algebraic completeness results for R-mingle and its extensions, Journal of Symbolic Logic 35 (1970), pp. 1?13.
4. G. Gr�tzer, General Lattice Theory, Birkhauser Verlag, Basel, 1978.
5. G. Gr�tzer, Universal Algebra, 2nd expanded ed., Springer Verlag, 1979.