@article{DE_1967_3_11_a1,
     author = {N. P. Erugin},
     title = {The analytic theory and problems in the real theory of differential equations, connected with the first method and with methods of the analytic theory},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1821--1863},
     publisher = {mathdoc},
     volume = {3},
     number = {11},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1967_3_11_a1/}
}