Khiem, Nguyen Tien, Duong The Hung, and Vu Thi An Ninh. “Multiple Crack Identification in Stepped Beam by Measurements of Natural Frequencies”. Vietnam Journal of Mechanics 36, no. 2 (June 10, 2014): 119–132. Accessed April 20, 2024. https://vjs.ac.vn/index.php/vjmech/article/view/3141.