A.O. Ilesanmi , S.O. Adejuwon , O.Y. Halid. “On A Method of Estimating the Hidden Population of Drug Addicts”. International Journal of Emerging Trends in Science and Technology, vol. 5, no. 01, Jan. 2018, pp. 6510-6, http://ijetst.in/index.php/ijetst/article/view/1246.