Al-Mukhaini, N., T. Ba-Omar, E. Eltayeb, and A. Al-Shehi. “Determination of Heavy Metals in the Common Smokeless Tobacco Afzal in Oman”. Sultan Qaboos University Medical Journal, vol. 14, no. 3, Aug. 2014, pp. 349-55, https://journals.squ.edu.om/index.php/squmj/article/view/1933.