@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/