Byoung Koo Lee, Sang Jin Oh, and Guangfan Li. “Buckling Loads of Columns of Regular Polygon Cross-Section With Constant Volume and Clamped Ends”. Electronic Journal of Structural Engineering 2 (January 1, 2002): 76–84. Accessed May 19, 2024. https://ejsei.com/EJSE/article/view/26.