A. Ratanasiri, T. Ratanasiri, T. Lam, and K. Cheng, “Medical Students’ Khowledge and Attitude Concerning Cigarrette smoking : A study in medical students at Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand”, SRIMEDJ, vol. 7, no. 1, pp. 18–27, Nov. 2013.