@article{1183528180, author = {Stenger, William}, title = {On Poincar\'e's bounds for higher eigenvalues}, journal = {Bull. Amer. Math. Soc.}, volume = {72}, number = {4}, year = {1966}, pages = { 715-718}, language = {en}, url = {http://dml.mathdoc.fr/item/1183528180} }
Stenger, William. On Poincaré's bounds for higher eigenvalues. Bull. Amer. Math. Soc., Tome 72 (1966) no. 4, pp. 715-718. http://gdmltest.u-ga.fr/item/1183528180/