@article{MZM_1997_62_2_a3,
     author = {D. V. Gorbachev},
     title = {An extremum problem on a class of differentiable functions of several variables},
     journal = {Matemati\v{c}eskie zametki},
     pages = {192--205},
     publisher = {mathdoc},
     volume = {62},
     number = {2},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1997_62_2_a3/}
}