Thang, Bui Xuan, Nguyen Xuan Hung, and Ngo Thanh Phong. 2010. “On Stabilization of the Node-Based Smoothed Finite Element Method for Free Vibration Problems”. Vietnam Journal of Mechanics 32 (3). Hanoi, Vietnam:167-81. https://doi.org/10.15625/0866-7136/32/3/303.