@article{SM_1989_63_2_a4,
     author = {V. A. Kondrat'ev and E. M. Landis},
     title = {On qualitative properties of solutions of a~nonlinear equation of second order},
     journal = {Sbornik. Mathematics},
     pages = {337--350},
     year = {1989},
     volume = {63},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1989_63_2_a4/}
}