@article{DAN_1958_121_4_a13,
     author = {B. V. Medvedev and M. K. Polivanov},
     title = {On a classical model of indefinite metric},
     journal = {Doklady Akademii Nauk},
     pages = {623--626},
     publisher = {mathdoc},
     volume = {121},
     number = {4},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_121_4_a13/}
}