@article{MZM_1987_41_1_a7,
     author = {M. S. Nikol'skii},
     title = {Approximation of the attainability set for a controlled process},
     journal = {Matemati\v{c}eskie zametki},
     pages = {71--76},
     publisher = {mathdoc},
     volume = {41},
     number = {1},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1987_41_1_a7/}
}