Yoo, Eun-Hyung and Soo-Youn Lee. "The prevalence and risk factors for gallstone disease" Clinical Chemistry and Laboratory Medicine, 47.7 (2009): 795-807. Retrieved 19 Jun. 2013, from doi:10.1515/CCLM.2009.194

Yoo, E. & Lee, S. (2009). The prevalence and risk factors for gallstone disease. Clinical Chemistry and Laboratory Medicine, 47(7), pp. 791-897. Retrieved 19 Jun. 2013, from doi:10.1515/CCLM.2009.194

Yoo, Eun-Hyung and Soo-Youn Lee. 2009. The prevalence and risk factors for gallstone disease. Clinical Chemistry and Laboratory Medicine. 47(7): 791-897. Retrieved 19 Jun. 2013, from doi:10.1515/CCLM.2009.194