Soheil Hashemi & Ali Asghar Jafari. (1970). An Analytical Solution for Nonlinear Vibration Analysis of Functionally Graded Rectangular Plate in Contact with Fluid.
            <i>Advances in Applied Mathematics and Mechanics</i>. <i>13</i> (4).
            914-941.
         doi:10.4208/aamm.OA-2019-0333