Ibrahim, Wedad, and Rafat Ghani. “Free Vibration Analysis of Laminated Composite Plates With General Elastic Boundary Supports”. Journal of Engineering 23, no. 4 (March 31, 2017): 100-124. Accessed October 27, 2020. http://joe.uobaghdad.edu.iq/index.php/main/article/view/54.