@article{1077490204, author = {Brown, Arthur B.}, title = {Critical curvatures in Riemannian spaces}, journal = {Duke Math. J.}, volume = {3}, number = {1}, year = {1937}, pages = { 473-483}, language = {en}, url = {http://dml.mathdoc.fr/item/1077490204} }
Brown, Arthur B. Critical curvatures in Riemannian spaces. Duke Math. J., Tome 3 (1937) no. 1, pp. 473-483. http://gdmltest.u-ga.fr/item/1077490204/