@article{DE_1989_25_6_a25,
     author = {P. V. Nikolenko},
     title = {On the structure of the pre-image of zero of a nonnegative solution of a homogeneous equation with a biharmonic principal part},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1058--1059},
     publisher = {mathdoc},
     volume = {25},
     number = {6},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_6_a25/}
}