@article{DAN_1961_136_3_a5,
     author = {V. P. Il'in and V. A. Solonnikov},
     title = {Some properties of differentiable functions of many variables},
     journal = {Doklady Akademii Nauk},
     pages = {538--541},
     publisher = {mathdoc},
     volume = {136},
     number = {3},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_136_3_a5/}
}