1. D. J. Brown andR. Suszko,Abstract Logics,Dissertationes Mathematicae, 102 (1973), pp. 7–41.
2. R. Wójcicki,On matrix representation of consequence operations of Łukasiewicz's sentential calculi,Zeitschrift für Mathematische Logik und Grundlagen der Mathematik, 19 (1973), pp. 239–247.
3. R. Suszko,Remarks on Łukasiewicz's three-valued logic,Bulletin of the Section of Logic, Polish Academy of Sciences, Institute of Philosophy and Sociology, Vol. 4, No. 3, 1975, pp. 87–90.
4. S. L. Bloom andD. J. Brown,Classical abstract logics,Dissertationes Mathematicae, 102 (1973), pp. 43–52.
5. S. L. Bloom andR. Suszko,Investigations into the Sentential Calculus with Identity,Notre Dame Journal of Formal Logic, 13 (1972), pp. 289–308.