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@article{DAN_1973_212_5_a13, author = {S. A. Chunikhin}, title = {On the definition of $\pi$-solvable and $\pi$-separable groups}, journal = {Doklady Akademii Nauk}, pages = {1078--1081}, publisher = {mathdoc}, volume = {212}, number = {5}, year = {1973}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1973_212_5_a13/} }
S. A. Chunikhin. On the definition of $\pi$-solvable and $\pi$-separable groups. Doklady Akademii Nauk, Tome 212 (1973) no. 5, pp. 1078-1081. http://geodesic.mathdoc.fr/item/DAN_1973_212_5_a13/