@article{DE_1973_9_3_a2,
     author = {Yu. M. Volin and G. M. Ostrovskii and A. V. Finkelstein},
     title = {The method of penalty functions and necessary optimality conditions for generalized solutions of an optimal control problem},
     journal = {Differencialʹnye uravneni\^a},
     pages = {423--429},
     publisher = {mathdoc},
     volume = {9},
     number = {3},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_3_a2/}
}