C. Selvaraj, and T. R. K. Kumar. “Bi-Univalent Coefficient Estimates for Certain Subclasses of Close-to-Convex Functions”. International Journal of Mathematics And Its Applications, vol. 3, no. 4 - D, Dec. 2015, pp. 69-74, https://ijmaa.in/index.php/ijmaa/article/view/516.