@article{IVM_1959_2_a8,
     author = {P. N. Knyazev},
     title = {On the use of minimax properties in perturbation theory},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {94--100},
     publisher = {mathdoc},
     number = {2},
     year = {1959},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1959_2_a8/}
}