@article{VMUMM_1993_1_a1,
     author = {M. Sugi},
     title = {On the number of lattice points in a disk in the {Lobachevskii} plane},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {8--14},
     year = {1993},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1993_1_a1/}
}