@article{1183733412, author = {Shoenfield, J. R.}, title = {Degrees of Formal Systems}, journal = {J. Symbolic Logic}, volume = {23}, number = {1}, year = {1958}, pages = { 389-392}, language = {en}, url = {http://dml.mathdoc.fr/item/1183733412} }
Shoenfield, J. R. Degrees of Formal Systems. J. Symbolic Logic, Tome 23 (1958) no. 1, pp. 389-392. http://gdmltest.u-ga.fr/item/1183733412/