Mirkhalaf Valashani, S.M. “Transverse Vibration of Clamped and Simply Supported Circular Plates With an Eccentric Circular Perforation and Attached Concentrated Mass”. Journal of Solid Mechanics, vol. 1, no. 1, Apr. 2009, pp. 37-44, https://oiccpress.com/jsm/article/view/12005.