Suntchai Wirotsaengthong, S. W., and J. Opanuraks. “The Muitivial Dose Lidocaine Can Be Contaminated by Body Secretion”. Insight Urology, vol. 31, no. 1, June 2010, pp. 47-51, https://he02.tci-thaijo.org/index.php/TJU/article/view/252340.