DRAGOMIR, Silvestru Sever. “Some Bessel Type Additive Inequalities in Inner Product Spaces”. Studia Universitatis Babeș-Bolyai Mathematica 66, no. 2 (June 30, 2021): 381–395. Accessed January 19, 2026. https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1336.