Hauk, N. Influence on Energy Efficiency of Mechanisms Operated With Hydraulic Cylinders. Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XIV, Inginerie mecanică = Annals of “Dunarea de Jos“ University of Galati. Fascicle XIV, Mechanical Engineering 2013, 20, 53-56.