@article{DAN_1990_313_1_a3,
     author = {N. D. Pokrovskaya},
     title = {Forced periodic regimes in control systems with regularization by},
     journal = {Doklady Akademii Nauk},
     pages = {21--24},
     publisher = {mathdoc},
     volume = {313},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_313_1_a3/}
}