@article{DE_1973_9_6_a0,
     author = {Ya. V. Bykov and N. I. Fomina},
     title = {The singular solutions of nonlinear differential {equations.~I}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {983--994},
     publisher = {mathdoc},
     volume = {9},
     number = {6},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1973_9_6_a0/}
}