@article{1177696719,
author = {Dykstra, Richard L.},
title = {Establishing the Positive Definiteness of the Sample Covariance Matrix},
journal = {Ann. Math. Statist.},
volume = {41},
number = {6},
year = {1970},
pages = { 2153-2154},
language = {en},
url = {http://dml.mathdoc.fr/item/1177696719}
}
Dykstra, Richard L. Establishing the Positive Definiteness of the Sample Covariance Matrix. Ann. Math. Statist., Tome 41 (1970) no. 6, pp. 2153-2154. http://gdmltest.u-ga.fr/item/1177696719/