@article{1183732765, author = {Friedberg, Richard}, title = {A Criterion for Completeness of Degrees of Unsolvability}, journal = {J. Symbolic Logic}, volume = {22}, number = {1}, year = {1957}, pages = { 159-160}, language = {en}, url = {http://dml.mathdoc.fr/item/1183732765} }
Friedberg, Richard. A Criterion for Completeness of Degrees of Unsolvability. J. Symbolic Logic, Tome 22 (1957) no. 1, pp. 159-160. http://gdmltest.u-ga.fr/item/1183732765/