Giambattista Amati and Fiora Pirri. A uniform tableau method for intuitionistic modal logics I.Studia Logica, 53:29–60, 1994.
Melvin C. Fitting.Proof Methods for Modal and Intuitionistic Logics. D. Reidel Publishing Co., Dordrecht, 1983.
Melvin C. Fitting. Destructive modal resolution.Journal of Logic and Computation, 1:83–97, 1990.
Melvin C. Fitting.First-Order Logic and Automated Theorem Proving. Springer-Verlag, 1990.
Melvin C. Fitting. Many-valued modal logics.Fundamenta Informaticae, 15:235–254, 1992.
Melvin C. Fitting. Many-valued modal logics, II.Fundamenta Informaticae, 17:55–73, 1992.
Melvin C. Fitting. Many-valued non-monotonic modal logics. In Anil Nerode and Mikhail Taitslin, editors,Logical Foundations of Computer Science — Tver '92, pages 139–150. Springer Lecture Notes in Computer Science, 620, 1992.
Melvin C. Fitting. Basic modal logic. In Dov M. Gabbay, C. J. Hogger, and J. A. Robinson, editors,Handbook of Logic in Artificial Intelligence and Logic Programming, volume 1, pages 368–448. Oxford University Press, 1993.
Charles G. Morgan. Local and global operators and many-valued modal logics.Notre Dame Journal of Formal Logic, 20:401–411, 1979.
Osamu Morikawa. Some modal logics based on a three-valued logic.Notre Dame Journal of Formal Logic, 30:130–137, 1989.
Pascal Ostermann. Many-valued modal propositional calculi.Zeitschrift für mathematische Logik und Gründlagen der Mathematik, 34:343–354, 1988.
Pascal Ostermann. Many-valued modal logics: Uses and predicate calculus.Zeitschrift für mathematische Logik und Gründlagen der Mathematik, 36:367–376, 1990.
Gordon Plotkin and Colin Stirling. A framework for intuitionistic modal logics, extended abstract. In Joseph Y. Halpern, editor,Theoretical Aspects of Reasoning About Knowledge, Proceedings of the 1986 Conference, pages 399–406. Morgan Kaufmann, 1986.
Helena Rasiowa and Roman Sikorski.The Mathematics of Metamathematics. PWN — Polish Scientific Publishers, Warsaw, third edition, 1970.
Peter K. Schotch, Jorgen B. Jensen, Peter F. Larsen, and Edwin J. MacLellan. A note on three-valued modal logic.Notre Dame Journal of Formal Logic, 19:63–68, 1978.
Krister Segerberg. Some modal logics based on a three-valued logic.Theoria, 33:53–71, 1967.
G. Fischer Servi. Axiomatizations for some intuitionistic modal logics.Rend. Sem. Mat. Univers. Polit., 42:179–194, 1984.
Raymond M. Smullyan.First-Order Logic. Springer-Verlag, 1968. Somewhat revised edition, Dover Press, NY, 1994.
S. K. Thomason. Possible worlds and many truth values.Studia Logica, 37:195–204, 1978.