Lueprapai, M. ., and M. Vongsaisuwon. “Can "Fluctuation of the Fluid Level" Predict ‘the Position of the Tip of Central Venous Catheter’ ?”. The Thai Journal of Surgery, vol. 25, no. 4, Dec. 2004, pp. 125-8, https://he02.tci-thaijo.org/index.php/ThaiJSurg/article/view/242288.