@article{DAN_1985_283_2_a5,
     author = {A. M. Krasnosel'skii},
     title = {One-sided estimates in a problem of forced oscillations in nonlinear control systems},
     journal = {Doklady Akademii Nauk},
     pages = {284--286},
     publisher = {mathdoc},
     volume = {283},
     number = {2},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1985_283_2_a5/}
}