Comparative study on the applicability of "extrusion" command in the design software taught in higher education institutions - Goanță, Adrian (Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XIV, Inginerie mecanică = Annals of “Dunarea de Jos“ University of Galati. Fascicle XIV, Mechanical Engineering, 2012)