“Closed (St-Closed) Compressible Modules and Closed (St-Closed) Retractable Modules”. Iraqi Journal of Science 65, no. 4 (April 30, 2024): 2141–2149. Accessed July 27, 2024. https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/9011.