@article{IVM_1994_3_a8,
     author = {\`E. G. Poznyak and A. G. Popov},
     title = {Lobachevskij geometry and physics},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {44--49},
     publisher = {mathdoc},
     number = {3},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1994_3_a8/}
}