Pourhoseingholi, M.A., Vahedi, M. and Rahimzadeh, M. 2013. Sample size calculation in medical studies. Gastroenterology and Hepatology from Bed to Bench. 6, 1 (Jan. 2013), Gastroenterol Hepatol Bed Bench 2013;6(1):14–17. DOI:https://doi.org/10.22037/ghfbb.v6i1.332.