Ojha, B. P., and P. M. Bajracharya. “Some Remarks on the Generalization of Orthogonality in Terms of Operators”. Methods of Functional Analysis and Topology 27, no. 4 (December 25, 2021): 302–307. Accessed December 15, 2025. https://zen.imath.kiev.ua/index.php/mfat/article/view/804.