@article{SM_1987_57_2_a9,
     author = {F. V. Guseinov},
     title = {A~general existence theorem for multidimensional extremal problems},
     journal = {Sbornik. Mathematics},
     pages = {455--461},
     publisher = {mathdoc},
     volume = {57},
     number = {2},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1987_57_2_a9/}
}