“The approximate or exact analytical solutions for the differential equations which describe parametric free vibrations of mechanical systems” (2013) Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XIV, Inginerie mecanică = Annals of “Dunarea de Jos“ University of Galati. Fascicle XIV, Mechanical Engineering, 20(1), pp. 65–68. Available at: https://ojs.ugal.ro/index.php/im/article/view/3556 (Accessed: 2 November 2026).