Aboud, Sabah, and Buthaina Abdul Hassan. “Invertible Operators on Soft Normed Spaces”. Iraqi Journal of Science 61, no. 5 (May 28, 2020): 1089-1097. Accessed November 27, 2021. https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/1376.