@article{DE_1968_4_9_a1,
     author = {A. F. Andreev and T. V. Stepanova},
     title = {The number of {Frommer} substitutions sufficient to reveal all ${\rm TO}$-curves of the equation $X(x,\,y)\,dy=Y(x,\,y)\,dx$},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1560--1573},
     publisher = {mathdoc},
     volume = {4},
     number = {9},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_9_a1/}
}