Kalinnikov А. Е. “Numerical Investigation of Forced Vibrations of Mechanical System under Harmonic Loads With Different Frequencies”. Vestnik IzhGTU Imeni M.T. Kalashnikova, vol. 18, no. 4, Dec. 2015, pp. 84-88, https://izdat.istu.ru/index.php/vestnik/article/view/3138.