Kashuri, A., and R. Liko. “Fractional Trapezium Type Inequalities for Twice Differentiable Preinvex Functions and Their Applications”. An International Journal of Optimization and Control: Theories & Applications (IJOCTA), vol. 10, no. 2, July 2020, pp. 226-3, doi:10.11121/ijocta.01.2020.00795.