วรุณโรจน์ จ. . “A Study of the Thickness on the Natural Frequency in the Free Vibration of Clamped - Clamped Steel Plate”. Journal of Engineering, RMUTT, vol. 1, June 2013, pp. 61-67, https://ph01.tci-thaijo.org/index.php/jermutt/article/view/242092.