@article{SEMR_2016_13_a50,
     author = {A. V. Kostin and N. N. Kostina},
     title = {An interpretation of {Casey{\textquoteright}s} theorem and of its hyperbolic analogue},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {242--251},
     publisher = {mathdoc},
     volume = {13},
     year = {2016},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2016_13_a50/}
}