@article{MZM_1990_47_4_a6,
     author = {E. Ya. Markushina},
     title = {Universal central extensions of groups of special automorphisms of free groups},
     journal = {Matemati\v{c}eskie zametki},
     pages = {46--54},
     publisher = {mathdoc},
     volume = {47},
     number = {4},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_47_4_a6/}
}