Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1971_7_6_a19, author = {V. B. Kolmanovskii}, title = {Solutions of constant sign for equations of neutral type}, journal = {Differencialʹnye uravneni\^a}, pages = {1116--1119}, publisher = {mathdoc}, volume = {7}, number = {6}, year = {1971}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1971_7_6_a19/} }
V. B. Kolmanovskii. Solutions of constant sign for equations of neutral type. Differencialʹnye uravneniâ, Tome 7 (1971) no. 6, pp. 1116-1119. http://geodesic.mathdoc.fr/item/DE_1971_7_6_a19/