1. Berestovskiĭ V. N., “Homogeneous spaces with intrinsic metric,” Dokl. Akad. Nauk SSSR, 301, No. 2, 268–271 (1988).
2. Berestovskiĭ V. N., “Homogeneous manifolds with intrinsic metric. I,” Siberian Math. J., 29, No. 6, 887–897 (1988).
3. Berestovskiĭ V. N., “Homogeneous manifolds with intrinsic metric. II,” Siberian Math. J., 30, No. 2, 180–191 (1989).
4. Pontryagin L. S., Boltyanskiĭ V. G., Gamkrelidze R. V., and Mishchenko E. F., Mathematical Theory of Optimal Processes [in Russian], Nauka, Moscow (1969).
5. Berestovskiĭ V. N., “Geodesics of nonholonomic left-invariant intrinsic metrics on the Heisenberg group and isoperimetric curves on the Minkowski plane,” Siberian Math. J., 35, No. 1, 1–8 (1994).