@article{DAN_1982_267_3_a2,
     author = {M. I. Zelikin},
     title = {Conditions for optimality of singular trajectories in the problem of minimizing a curvilinear integral},
     journal = {Doklady Akademii Nauk},
     pages = {528--531},
     publisher = {mathdoc},
     volume = {267},
     number = {3},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1982_267_3_a2/}
}