1. V. N. Berestovskii, “Homogeneous manifolds with intrinsic metric. I,” Sibirsk. Mat. Zh.,29, No. 6, 17–29 (1988).
2. V. N. Berestovskii, “Homogeneous spaces with intrinsic metric,” Dokl. Akad. Nauk SSSR,301, No. 2, 268–271 (1988).
3. L. S. Pontryagin, V. G. Boltyanskii, R. V. Gamkrelidze, and E. F. Mishchenko, Mathematical Theory of Optimal Processes [in Russian], Nauka, Moscow (1969).
4. H. Busemann, The Geometry of Geodesics [Russian translation], Fizmatgiz, Moscow (1962).
5. K. Leichtweiss, Convex Sets [Russian translation], Nauka, Moscow (1985).