@article{DE_1981_17_6_a10,
     author = {G. V. Sherbina},
     title = {Nonlinear boundary value problems for second-order equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1050--1059},
     publisher = {mathdoc},
     volume = {17},
     number = {6},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1981_17_6_a10/}
}