@article{IVM_1997_6_a1,
     author = {V. V. Petrova and E. L. Tonkov},
     title = {The admissibility of periodic processes and existence theorems for periodic {solutions.~II}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {17--24},
     publisher = {mathdoc},
     number = {6},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1997_6_a1/}
}