@article{VMUMM_1989_2_a7,
     author = {A. Yu. Ol'shanskii},
     title = {Efficient embeddings of countable groups},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {28--34},
     year = {1989},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1989_2_a7/}
}