Galib Atshan, Waggas, and Rajaa Ali Hiress. “Coefficient Estimates for Subclasses of Bi-Univalent Functions”. Journal of Al-Qadisiyah for computer science and mathematics 10, no. 3 (August 5, 2018): Math Page 20 - 26. Accessed August 30, 2021. http://www.qu.edu.iq/journalcm/index.php/journalcm/article/view/401.