Concepts and principles of the sustainable digital technologies use: process science and activity theory viewAlexander S. Geyda, Lyudmila N. Fedorchenko, Igor V. Lysenko, Aleksandra S. Svistunova and Dmitry S. KhasanovE3S Web Conf., 311 (2021) 07005DOI: https://doi.org/10.1051/e3sconf/202131107005