Wataganara, Tuangsit, Pattarawalai Talungjit, Nisarat Phithakwatchara, and Siripong Swasdimongkol. “Three Dimensional Sonographic Appearances of Chinese Ring Intrauterine Device:”. Siriraj Medical Journal 60, no. 6 (November 1, 2008): 360–363. Accessed May 6, 2024. https://he02.tci-thaijo.org/index.php/sirirajmedj/article/view/246512.