@article{SEMR_2013_10_a28,
     author = {L. N. Romakina},
     title = {Analogs of a formula of {Lobachevsky} for angle of parallelism on the hyperbolic plane of positive curvature},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {393--407},
     publisher = {mathdoc},
     volume = {10},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2013_10_a28/}
}