@article{IVM_1972_5_a6,
     author = {P. P. Zabreiko and M. A. Krasnosel'skii and V. V. Strygin},
     title = {Invariance of rotation principles},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {51--57},
     publisher = {mathdoc},
     number = {5},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1972_5_a6/}
}