Providing feedback for students in E-learning systems : a literature review, based on IEEE Explore Digital LibraryShvets, Oleg; Murtazin, Kristina; Piho, GunnarProceedings of the 2020 IEEE Global Engineering Education Conference (EDUCON) : Engineering Education for the Future in a Multicultural and Smart World, 27-30 April, 2020, Porto, Portugal2020 / p. 284-289 : ill https://doi.org/10.1109/EDUCON45650.2020.9125344