Martynyuk A. The conditions of Hyers—Ulam—Rassias-stability of a set of equations . Dopov. Nac. akad. nauk Ukr. [Internet]. 2017 Aug. 28 [cited 2026 Jun. 20];(8):11-6. Available from: https://nasu-periodicals.org.ua/index.php/dp/article/view/7688