BUDAK H, SARIKAJA MZ. An inequality of Ostrowski-Grüss type for double integrals. Stud. Univ. Babeş-Bolyai Math. [Internet]. 2017 Jun. 15 [cited 2025 Feb. 5];62(2):163-7. Available from: https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/1771