Hasan, H.S. (2017) “Air Gap Effect on the Properties of Unsaturated Symmitrical Double Polepiece Lenses”, Ibn AL-Haitham Journal For Pure and Applied Sciences, 21(1), pp. 49–61. Available at: https://jih.uobaghdad.edu.iq/index.php/j/article/view/1375 (Accessed: 15 March 2025).