1. M. A. Akivis, “The focal images of a surface of rank r,” Izv. Vyssh. Uchebn. Zaved., Mat., No. 1, 9–19 (1957).
2. M. A. Akivis, “On the structure of conjugate systems on multidimensional surfaces,” Izv. Vyssh. Uchebn. Zaved., Mat., No. 10, 3–11 (1970).
3. V. T. Bazylev, “On multidimensional nets and their transformations,” in: Geometry [in Russian], 1963 (Itogi Nauki i Tekh. VINITI Akad. Nauk SSSR), Moscow (1965), pp. 138–164.
4. V. T. Bazylev, M. K. Kuz'min, and A. V. Stolyarov, “Nets on manifolds,” in: Problems in Geometry [in Russian], Vol. 12 (Itogi Nauki i Tekh. Akad. Nauk SSSR), Moscow (1981), pp. 97–125.
5. L. E. Evtushik, Yu. G. Lumiste, N. M. Ostianu, and A. P. Shirokov, “Differential-geometric structures on manifolds,” in: Problems in Geometry [in Russian], Vol. 9 (Itogi Nauki i Tekh. VINITI Akad. Nauk SSSR), Moscow (1979).