1. Bierman, G.M., de Paiva, V.C.V.: On an intuitionistic modal logic. Stud. Log.: Int. J. Symb. Log. 65(3), 383–416 (2000). http://www.jstor.org/stable/20016199
2. Božić, M., Došen, K.: Models for normal intuitionistic modal logics. Stud. Log. 43(3), 217–245 (1984)
3. Brouwer, L.E.J., Heyting, A.: L.E.J. Brouwer: Collected Works, Volume 1: Philosophy and Foundations of Mathematics. North-Holland Publishing Company, American Elsevier Publishing Company, New York (1975)
4. del Cerro, L.F.n., Herzig, A.: Modal deduction with applications in epistemic and temporal logics. In: Gabbay, D.M., Hogger, C.J., Robinson, J.A. (eds.) Handbook of Logic in Artificial Intelligence and Logic Programming (Vol. 4): Epistemic and Temporal Reasoning, pp. 499–594. Oxford University Press Inc., USA (1995)
5. del Cerro, L.F., Penttonen, M.: Grammar logics. Log. Anal. 31(121/122), 123–134 (1988)