@article{IVM_1974_2_a14,
     author = {V. I. Kholkin},
     title = {The principal frequency of an inhomogeneous annular membrane},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {121--123},
     year = {1974},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1974_2_a14/}
}