@article{TIMM_2007_13_1_a5,
     author = {A. V. Zavarnitsin and V. D. Mazurov},
     title = {On element orders in coverings of the simple groups $L_n(q)$ and $U_n(q)$},
     journal = {Trudy Instituta matematiki i mehaniki},
     pages = {89--98},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TIMM_2007_13_1_a5/}
}