Poomlek, V. ., W. . Chaitree, P. . Thongcharoen, P. Panchavinnin, and N. . Opartkiattikul. “A Comparative Study of Portable Monitors (CoaguCheck®XS) for International Normalized Ratio (INR)”. Siriraj Medical Journal, vol. 60, no. 1, Jan. 2008, pp. 10-13, https://he02.tci-thaijo.org/index.php/sirirajmedj/article/view/246293.