@article{1183386543, author = {Langford, C. H.}, title = {A Theorem on Deducibility for Second-Order Functions}, journal = {J. Symbolic Logic}, volume = {4}, number = {1}, year = {1939}, pages = { 77-79}, language = {en}, url = {http://dml.mathdoc.fr/item/1183386543} }
Langford, C. H. A Theorem on Deducibility for Second-Order Functions. J. Symbolic Logic, Tome 4 (1939) no. 1, pp. 77-79. http://gdmltest.u-ga.fr/item/1183386543/