T. Akeju, “Lyapunov Functional for Lateral Buckling of I Beams Subjected to Pure Bending”, Eng. Trans., vol. 30, no. 3-4, pp. 397–404, Dec. 1982, Accessed: Apr. 24, 2025. [Online]. Available: https://et3.ippt.pan.pl/index.php/et/article/view/1986