@article{SM_2017_208_9_a3,
     author = {A. A. Ershov and V. N. Ushakov},
     title = {An approach problem for a~control system with an unknown parameter},
     journal = {Sbornik. Mathematics},
     pages = {1312--1352},
     publisher = {mathdoc},
     volume = {208},
     number = {9},
     year = {2017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2017_208_9_a3/}
}