A. Badran, Hussain. “Experimental Evidence of an Optical Bistability Based on Self - Focusing”. University of Thi-Qar Journal of Science 3, no. 2 (February 2, 2012): 190–193. Accessed April 11, 2025. http://mail.jsci.utq.edu.iq/index.php/main/article/view/428.