@article{DAN_1990_314_1_a31,
     author = {V. N. Solov'ev},
     title = {Duality of nonconvex extremal problems},
     journal = {Doklady Akademii Nauk},
     pages = {135--138},
     publisher = {mathdoc},
     volume = {314},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_314_1_a31/}
}