@article{AA_2012_24_1_a1,
     author = {E. P. Vdovin and D. O. Revin and L. A. Shemetkov},
     title = {Formations of finite $C_\pi $-groups},
     journal = {Algebra i analiz},
     pages = {40--52},
     year = {2012},
     volume = {24},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2012_24_1_a1/}
}