Joshi, S. B., and P. K. Banerji. “Inequalities for Multivalent Functions Defined by Ruscheweyh Derivative”. The Journal of the Indian Mathematical Society, vol. 71, no. 1-4, Dec. 2004, pp. 233-7, https://informaticsjournals.co.in/index.php/jims/article/view/22046.