Dat, Pham Tien, Do Van Thom, and Doan Trac Luat. “Free Vibration of Functionally Graded Sandwich Plates With Stiffeners Based on the Third-Order Shear Deformation Theory”. Vietnam Journal of Mechanics 38, no. 2 (June 24, 2016): 103–122. Accessed June 27, 2022. https://vjs.ac.vn/index.php/vjmech/article/view/6730.