An Ninh, Vu Thi, Luu Quynh Huong, Tran Thanh Hai, and Nguyen Tien Khiem. 2017. “The Transfer Matrix Method for Modal Analysis of Cracked Multistep Beam”. <i>Vietnam Journal of Science and Technology</i> 55 (5). Hanoi, VN:598-611. https://doi.org/10.15625/2525-2518/55/5/9140.