Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MAT_1964_8_5_a8, author = {A. Weinstein}, title = {The intermediate problems and the maximum-minimum theory of eigenvalues}, journal = {Matematika}, pages = {91--101}, publisher = {mathdoc}, volume = {8}, number = {5}, year = {1964}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MAT_1964_8_5_a8/} }
A. Weinstein. The intermediate problems and the maximum-minimum theory of eigenvalues. Matematika, Tome 8 (1964) no. 5, pp. 91-101. http://geodesic.mathdoc.fr/item/MAT_1964_8_5_a8/