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@article{MZ_1973__130_171875, author = {Hans Wittich and G\"unter Frank}, title = {Zur {Theorie} linearer {Differenatialgleichungen} im {Komplexen.}}, journal = {Mathematische Zeitschrift}, pages = {363--370}, publisher = {mathdoc}, volume = {130}, year = {1973}, zbl = {0242.34003}, url = {http://geodesic.mathdoc.fr/item/MZ_1973__130_171875/} }
Hans Wittich; Günter Frank. Zur Theorie linearer Differenatialgleichungen im Komplexen.. Mathematische Zeitschrift, Tome 130 (1973), pp. 363-370. http://geodesic.mathdoc.fr/item/MZ_1973__130_171875/