https://ult.fmipa.uho.ac.id/wp-content/upgrade/
Alsait, A., and N. Alabbar. “Fekete -Szego Problem for Starlike of Complex Functions of Order Related  to Generalized  Derivative Operator    ”. Journal of Humanitarian and Applied Sciences, vol. 4, no. 8, Dec. 2019, pp. 321-3, https://khsj.elmergib.edu.ly/index.php/jhas/article/view/136.