@article{IVM_1971_12_a6,
     author = {P. Zenf},
     title = {A~certain theorem on groups with an invariant mean},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {63--65},
     publisher = {mathdoc},
     number = {12},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1971_12_a6/}
}