KAREEM, M. A.; JADER, J. A. Prevalence of Cigarette and “Waterpipe” Smoking among “Duhok Universities” Students. Polytechnic Journal, [S. l.], v. 9, n. 2, p. 63-69, 2019. DOI: 10.25156/ptj.v9n2y2019.pp63-69. Disponível em: https://journals.epu.edu.iq/index.php/polytechnic/article/view/24. Acesso em: 22 sep. 2020.