@article{MZM_1990_47_1_a5,
     author = {M. I. Zelikin and V. F. Borisov},
     title = {Synthesis in problems of optimal control containing trajectories with participating switchings and singular trajectories of the second order},
     journal = {Matemati\v{c}eskie zametki},
     pages = {62--73},
     publisher = {mathdoc},
     volume = {47},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_47_1_a5/}
}