Bertram C. Bruce. A logic for unknown outcomes. Notre Dame Journal of Formal Logic, 17(4):542-550, 1976. [doi]
@article{Bruce76, title = {A logic for unknown outcomes}, author = {Bertram C. Bruce}, year = {1976}, doi = {10.1305/ndjfl/1093887726}, url = {http://dx.doi.org/10.1305/ndjfl/1093887726}, researchr = {https://researchr.org/publication/Bruce76}, cites = {0}, citedby = {0}, journal = {Notre Dame Journal of Formal Logic}, volume = {17}, number = {4}, pages = {542-550}, }