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@article{DE_1969_5_9_a9, author = {A. G. Terent'ev}, title = {Certain properties of linear differential operators}, journal = {Differencialʹnye uravneni\^a}, pages = {1635--1641}, publisher = {mathdoc}, volume = {5}, number = {9}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1969_5_9_a9/} }
A. G. Terent'ev. Certain properties of linear differential operators. Differencialʹnye uravneniâ, Tome 5 (1969) no. 9, pp. 1635-1641. http://geodesic.mathdoc.fr/item/DE_1969_5_9_a9/