Sukhwinder Singh Billing and  Sushma Gupta and  Sukhjit Singh Dhaliwal,  Certain Conditions for Strongly Starlike and Strongly Convex Functions.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    July 2010, vol. 43(7). 1058 - 1060
    [viewed 21 October 2019]. Available from: https://publications.waset.org/pdf/8032.