Ivanov ГГ, Alferov ГВ, Korolev ВС. Derivative number apparatus and application possibilities. Вест. ПГУ. Мат. Мех. Инф. [Internet]. 2021 Oct. 30 [cited 2025 Apr. 5];(3 (54). Available from: https://press.psu.ru/index.php/Math/article/view/4936