@article{DA_1971_9_a4,
     author = {Yu. M. Volin and G. M. Ostrovskii},
     title = {The method of penalty functions, and necessary conditions for optimality},
     journal = {Diskretnyj analiz i issledovanie operacij},
     pages = {43--51},
     publisher = {mathdoc},
     number = {9},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DA_1971_9_a4/}
}