@article{RM_1993_48_2_a2,
     author = {A. P. Norden and A. P. Shirokov},
     title = {The heritage of {N.\,I.~Lobachevskii} and the activity of {Kazan} geometers},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {47--74},
     publisher = {mathdoc},
     volume = {48},
     number = {2},
     year = {1993},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1993_48_2_a2/}
}