Jarungjitaree, S., N. Chaipiyaporn, A. Santiworakul, and S. Cetthakrikul. “Effect of Smoking on Physical Activity Level and Pulmonary Function of Vocational Students in Bangkok”. Srinagarind Medical Journal, vol. 25, no. 4, Oct. 2013, pp. 287-91, https://li01.tci-thaijo.org/index.php/SRIMEDJ/article/view/12948.