@article{AL_1990_29_1_a6,
     author = {S. G. Chekanov},
     title = {Broad subgroups of some sporadic groups},
     journal = {Algebra i logika},
     pages = {82--101},
     year = {1990},
     volume = {29},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1990_29_1_a6/}
}