@article{1077489912, author = {Carlitz, Leonard}, title = {Sums of squares of polynomials}, journal = {Duke Math. J.}, volume = {3}, number = {1}, year = {1937}, pages = { 1-7}, language = {en}, url = {http://dml.mathdoc.fr/item/1077489912} }
Carlitz, Leonard. Sums of squares of polynomials. Duke Math. J., Tome 3 (1937) no. 1, pp. 1-7. http://gdmltest.u-ga.fr/item/1077489912/