Atshan, Waggas Galib, et al. “New Concept on Fourth-Order Differential Subordination and Superordination With Some Results for Multivalent Analytic Functions”. Journal of Al-Qadisiyah for Computer Science and Mathematics, vol. 12, no. 1, Mar. 2020, pp. Math Page 96-107, doi:10.29304/jqcm.2020.12.1.681.