@article{1093891883, author = {Purtill, Richard L.}, title = {Paradox-free deontic logics.}, journal = {Notre Dame J. Formal Logic}, volume = {16}, number = {1}, year = {1975}, pages = { 483-490}, language = {en}, url = {http://dml.mathdoc.fr/item/1093891883} }
Purtill, Richard L. Paradox-free deontic logics.. Notre Dame J. Formal Logic, Tome 16 (1975) no. 1, pp. 483-490. http://gdmltest.u-ga.fr/item/1093891883/