@article{ZNSL_1998_252_a2,
     author = {V. A. Zalgaller and O. M. Merkulova},
     title = {Analogues of the {Appollonian} circle on the {Lobachevsky} plane and on sphere},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {21--32},
     publisher = {mathdoc},
     volume = {252},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1998_252_a2/}
}