@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},
     year = {1964},
     volume = {8},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1964_8_5_a8/}
}