@article{DAN_1961_138_5_a9,
     author = {Ya. D. Polovitskii},
     title = {Locally extremal groups and groups with $\pi$-minimality condition},
     journal = {Doklady Akademii Nauk},
     pages = {1022--1024},
     publisher = {mathdoc},
     volume = {138},
     number = {5},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_138_5_a9/}
}