أحمد م. ., قبلان ن. ., and عمران س. . . “An Analytical Study of Diffraction of Light by a Circular Aperture Using Spherical Harmonics for n≤2”. Tishreen University Journal -Basic Sciences Series, vol. 42, no. 4, Oct. 2020, https://journal.tishreen.edu.sy/index.php/bassnc/article/view/9950.