@article{1077472371,
author = {Williamson, John},
title = {Hadamard's determinant theorem and the sum of four squares},
journal = {Duke Math. J.},
volume = {11},
number = {1},
year = {1944},
pages = { 65-81},
language = {en},
url = {http://dml.mathdoc.fr/item/1077472371}
}
Williamson, John. Hadamard’s determinant theorem and the sum of four squares. Duke Math. J., Tome 11 (1944) no. 1, pp. 65-81. http://gdmltest.u-ga.fr/item/1077472371/