7 Puentes y conectores.......................................................................................139
8 Obtención de ayuda........................................................................................ 144
............................................................................................................................. 144
............................................................................................................. 135
....................................................................................................................... 136
..................................................................................... 139
............................................................................................................ 140
..................................................................................... 142
.............................................................................................. 144
....................................................................................................... 145
...............................................................................137
.................................................................. 138
.............................................................................145
....................................... 137
...................... 137
............137
7