Kalinnikov А. Е., and Kuznetsov Н. П. “Numerical Investigation of Parametrical Vibrations of Beam”. Vestnik IzhGTU Imeni M.T. Kalashnikova, vol. 19, no. 1, Apr. 2016, pp. 3-6, https://izdat.istu.ru/index.php/vestnik/article/view/3154.