@article{1077474295, author = {Cohen, Eckford}, title = {Sums of an even number of squares in $GF[p^n,x]$ , II}, journal = {Duke Math. J.}, volume = {14}, number = {1}, year = {1947}, pages = { 543-557}, language = {en}, url = {http://dml.mathdoc.fr/item/1077474295} }
Cohen, Eckford. Sums of an even number of squares in $GF[p^n,x]$ , II. Duke Math. J., Tome 14 (1947) no. 1, pp. 543-557. http://gdmltest.u-ga.fr/item/1077474295/