1. Reshetnyak Yu. G., Space Mappings with Bounded Distortion, Amer. Math. Soc., Providence (1989) (Transl. Math. Monogr.; vol. 73).
2. Vodopyanov S. K., “Differentiability of mappings of the Sobolev class W1 n−1 with some conditions on a distortion function,” Sib. Math. J., vol. 59, no. 6 (2018).
3. Stepanoff W., “Sur les conditions de l’existence de la differentiate totale,” Mat. Sb., vol. 32, 511–526 (1925).
4. Saks S., Theory of the Integral, Hafner Publishing Company, New York (1937).
5. Whitney H., “On totally differentiable and smooth functions,” Pacific J. Math., vol. 1, 143–159 (1951).