Spontaneous surgery on the Borromean rings. Pashkevich, M.G. — 2003 Sibirskij Matematicheskij Zhurnal
Elementary formulas for a hyperbolic tetrahedron. Mednykh, A.D.; Pashkevich, M.G. — 2006 Sibirskij Matematicheskij Zhurnal
On the volume of a symmetric tetrahedron in hyperbolic and spherical spaces. Derevnin, D.A.; Mednykh, A.D.; Pashkevich, M.G. — 2004 Sibirskij Matematicheskij Zhurnal