Drăgan, Nicușor. Considerations on the Nonlinearity Grade of the Nonlinear Mechanical Elastic Systems. Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XIV, Inginerie mecanică = Annals of “Dunarea de Jos“ University of Galati. Fascicle XIV, Mechanical Engineering 19, no. 1 (juin 1, 2012): 13-18. Consulté le septembre 27, 2025. https://www.gup.ugal.ro/ugaljournals/index.php/im/article/view/3680.