1. G. M. Fikhtengol'ts, Course in Differential and Integral Calculus [in Russian], Vol. 1, Fizmatgiz, Moscow (1962).
2. P. K. Rashevskii, Course in Differential Geometry [in Russian], Gostekhizdat, Moscow (1956).
3. D. Hilbert and S. Cohn-Vossen, Intuitive Geometry [Russian translatial], Gostekhizdat, Moscow (1951).
4. V. T. Vodnev et al., Collection of Problems and Exercises on Differential Geometry [in Russian], Vyshéishaya Shkola, Minsk (1970).
5. S. H. Schot, ?Aberrancy: geometry of the third derivative,? Math. Mag.,51, No. 5, 259?275 (1978).