Silsirivanit, A., S. Proungvitaya, K. Sawanyawisuth, C. Wongkham, and S. Wongkham. “Biomarkers in Bile Duct Cancers: Current Status”. Srinagarind Medical Journal, vol. 27, Aug. 2013, pp. 405-12, https://li01.tci-thaijo.org/index.php/SRIMEDJ/article/view/11166.