Influence of the behavior of nonlinear viscoelastic systems bearing on the dynamics of bridge structures - Leopa, Adrian; Nastac, Silviu (Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XIV, Inginerie mecanică = Annals of “Dunarea de Jos“ University of Galati. Fascicle XIV, Mechanical Engineering, 2011)