@article{DAN_1988_303_5_a5,
     author = {N. P. Osmolovskii},
     title = {Higher-order necessary and sufficient conditions for {Pontryagin}},
     journal = {Doklady Akademii Nauk},
     pages = {1052--1056},
     publisher = {mathdoc},
     volume = {303},
     number = {5},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_303_5_a5/}
}