@article{MT_2006_9_1_a7,
     author = {M. A. Cheshkova},
     title = {Congruences of {Hypersheres}},
     journal = {Matemati\v{c}eskie trudy},
     pages = {169--175},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_2006_9_1_a7/}
}