Hadi, Inaam M. A., and Sameeah Hasoon Aidi. “δ-Hollow Modules”. Ibn AL-Haitham Journal For Pure and Applied Sciences 27, no. 2 (April 17, 2017): 241–250. Accessed March 30, 2025. https://jih.uobaghdad.edu.iq/index.php/j/article/view/348.