1. Alechina, N., Mendler, M., de Paiva, V., Ritter, E. (2001). Categorical and Kripke semantics for constructive S4 modal logic. In Computer science logic (Paris, 2001). Lecture notes in comput. sci. (Vol. 2142, pp. 292–307). Berlin: Springer.
2. Baltag, A., Coecke, B., Sadrzadeh, M. (2007). Epistemic actions as resources. Journal of Logic and Computation, 17(3), 555–585.
3. Blackburn, P., de Rijke, M., Venema, Y. (2001). Modal logic. In Cambridge tracts in theoretical computer science (Vol. 53). Cambridge: Cambridge University Press.
4. Blackburn, P., van Benthem, J., Wolter, F. (Eds.) (2007). Handbook of modal logic. Studies in logic and practical reasoning (Vol. 3). Amsterdam: Elsevier.
5. Davey, B.A., & Galati, J.C. (2003). A coalgebraic view of Heyting duality. Studia Logica, 75(3), 259–270.