Anil Gupta. Modal logic and truth. J. Philosophical Logic, 7(1):441-472, 1978. [doi]
@article{Gupta78-0, title = {Modal logic and truth}, author = {Anil Gupta}, year = {1978}, doi = {10.1007/BF00245939}, url = {http://dx.doi.org/10.1007/BF00245939}, researchr = {https://researchr.org/publication/Gupta78-0}, cites = {0}, citedby = {0}, journal = {J. Philosophical Logic}, volume = {7}, number = {1}, pages = {441-472}, }