@article{SMZ_2005__46_2_52059,
     author = {Aseev, V.V. and Sychev, A.V. and Tetenov, A.V.},
     title = {M\"obius-invariant metrics and generalized angles in {Ptolemaic} spaces.},
     journal = {Sibirskij Matematicheskij Zhurnal},
     pages = {243},
     publisher = {mathdoc},
     volume = {46},
     number = {2},
     year = {2005},
     zbl = {1080.54019},
     language = {en},
     url = {https://geodesic-test.mathdoc.fr/item/SMZ_2005__46_2_52059/}
}