@article{DAN_1980_250_4_a11,
     author = {\'E. V. Nikol'skii},
     title = {Generalized functionally invariant solutions of two-dimensional equations of second order and systems of first order},
     journal = {Doklady Akademii Nauk},
     pages = {812--815},
     publisher = {mathdoc},
     volume = {250},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1980_250_4_a11/}
}