Dong, Dang Thuy, and Dao Van Dung. “Nonlinear Vibration of Functionally Graded Material Sandwich Doubly Curved Shallow Shells Reinforced by FGM Stiffeners. Part 1: Governing Equations”. <i>Vietnam Journal of Mechanics</i> 39, no. 3 (September 23, 2017): 245–257. Accessed November 8, 2025. https://vjmech.vast.vn/vjmech/article/view/9692.