Rebhi, Sami. “Equivalence of K-Functionals and Modulus of Smoothness Generated by The $ Q $-Rubin Operator”. Sarajevo Journal of Mathematics 15, no. 1 (March 7, 2022): 49–56. Accessed October 15, 2024. https://sjm.anubih.ba/index.php/sjm/article/view/47.