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@article{DE_1973_9_7_a4, author = {Yu. I. Zubko and V. A. Tyshkevich}, title = {On the question of the positivity of a {Cauchy} function}, journal = {Differencialʹnye uravneni\^a}, pages = {1207--1213}, publisher = {mathdoc}, volume = {9}, number = {7}, year = {1973}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1973_9_7_a4/} }
Yu. I. Zubko; V. A. Tyshkevich. On the question of the positivity of a Cauchy function. Differencialʹnye uravneniâ, Tome 9 (1973) no. 7, pp. 1207-1213. http://geodesic.mathdoc.fr/item/DE_1973_9_7_a4/