M. M. Ahmad Iqbal, M. M. Ahsan Iqbal, M. F. Ashraf, Z. Mehmood, and U. Ali, “Transition from Smoking Drugs to Injectable Drugs: Causes and Consequences”, Pak. J. Nutr., vol. 14, no. 8, pp. 535–539, Jul. 2015, doi: 10.3923/pjn.2015.535.539.