@article{DE_1993_29_6_a19,
     author = {V. I. Gromak},
     title = {B\"acklund transformations of nonlinear equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1067--1068},
     publisher = {mathdoc},
     volume = {29},
     number = {6},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_6_a19/}
}