@article{1183389242, author = {Rosser, Barkley}, title = {The Independence of Quine's Axioms $^\ast 200$ and $^\ast 201$}, journal = {J. Symbolic Logic}, volume = {6}, number = {1}, year = {1941}, pages = { 96-97}, language = {en}, url = {http://dml.mathdoc.fr/item/1183389242} }
Rosser, Barkley. The Independence of Quine's Axioms $^\ast 200$ and $^\ast 201$. J. Symbolic Logic, Tome 6 (1941) no. 1, pp. 96-97. http://gdmltest.u-ga.fr/item/1183389242/