@article{SEMR_2022_19_2_a21,
     author = {A. V. Kostin},
     title = {On generalizations of {Ptolemy's} theorem on the {Lobachevsky} plane},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {404--414},
     publisher = {mathdoc},
     volume = {19},
     number = {2},
     year = {2022},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2022_19_2_a21/}
}