@article{DE_1993_29_10_a10,
     author = {V. F. Kovalev and V. V. Pustovalov and S. I. Senashov},
     title = {The {Lie--B\"acklund} group of the equations of nonlinear geometric optics},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1751--1764},
     publisher = {mathdoc},
     volume = {29},
     number = {10},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_10_a10/}
}