1. S. Giambrone, Gentzen Systems and Decision Procedures for Relevant Logics, Australian National University Doctoral Dissertation, 1983.
2. S. Giambrone and A. Urquhart, Proof theories for semilattice logics, Zeitshrift für Mathematische Logik und Grundlagen der Mathematik 33 (1987).
3. A. Urquhart, Semantics for relevant logics, The Journal of Symbolic Logic 37 (1972), pp. 159?69.
4. , The Semantics of Entaliment, University of Pittsburgh Doctoral Dissertation, Ann Arbor (University Microfilms) 1973.
5. K. Fine, Completeness for the semi-lattice semantics (Abstract), The Journal of Symbolic Logic 41 (1976), p. 560.