@article{1250128038, author = {Greenfield, Gary R.}, title = {Sums of three and four integer squares}, journal = {Rocky Mountain J. Math.}, volume = {13}, number = {4}, year = {1983}, pages = { 169-176}, language = {en}, url = {http://dml.mathdoc.fr/item/1250128038} }
Greenfield, Gary R. Sums of three and four integer squares. Rocky Mountain J. Math., Tome 13 (1983) no. 4, pp. 169-176. http://gdmltest.u-ga.fr/item/1250128038/