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), 65-68. https://ojs.ugal.ro/index.php/im/article/view/3556