@article{DAN_1958_123_1_a2,
     author = {I. A. Bakhtin and M. A. Krasnosel'skii},
     title = {On the theory of equations with concave operators},
     journal = {Doklady Akademii Nauk},
     pages = {17--20},
     publisher = {mathdoc},
     volume = {123},
     number = {1},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_123_1_a2/}
}