@article{DE_1979_15_9_a4,
     author = {S. G. Kondratenya},
     title = {Characterizations of the complexity of singular points of solutions to nonlinear systems of two differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1580--1591},
     publisher = {mathdoc},
     volume = {15},
     number = {9},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1979_15_9_a4/}
}