@article{DAN_1960_133_2_a8,
     author = {M. I. Red'kov},
     title = {The domain of the values of functional 
},
     journal = {Doklady Akademii Nauk},
     pages = {284--287},
     publisher = {mathdoc},
     volume = {133},
     number = {2},
     year = {1960},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_133_2_a8/}
}