PROYECCIONES http://www.youtube.com/watch?v=6_snOA7r2oQ&feature=player_embedded#! http://www.youtube.com/watch?v=vNWCDOG4rr8&feature=related http://www.youtube.com/watch?v=QP5F30t9coQ&feature=related CORTES http://www.terra.es/personal8/jcuadr2/norma/index2.htm http://www.youtube.com/watch?v=2iQdqZeSY0o&feature=related USO ESCUADRAS http://www.youtube.com/watch?v=pTyYkRfU3xI&feature=related http://www.youtube.com/watch?v=tqyAGB7RzWg&NR=1 PROY ISOMETR. http://www.azucarysal.es/apuntes/Web_Dibujo/perspectivas.html