@article{DE_1973_9_9_a18,
     author = {S. Ya. Gorokhovik},
     title = {Necessary conditions for the optimality of multidimensional singular controls},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1721--1724},
     publisher = {mathdoc},
     volume = {9},
     number = {9},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_9_a18/}
}