1. D. Hilbert and S. Cohn-Vossen, Anschauliche Geometrie (Julius Springer, Berlin, 1932; Nauka, Moscow, 1981).
2. V. F. Kagan, Foundations of Surface Theory in Tensor Exposition (Gostekhizdat, Moscow, 1947–1948), Parts 1, 2 [in Russian].
3. A. V. Pogorelov, Lectures on Differential Geometry (Izd. Kharkov. Gos. Univ., Kharkov, 1956) [in Russian].
4. P. K. Rashevskii, A Course in Differential Geometry (GONTI, Moscow, 1938) [in Russian].
5. A. V. Pogorelov, Geometric Methods in the Nonlinear Theory of Elastic Shells (Nauka, Moscow, 1967) [in Russian].