MANEJAR EL RATÓN EN 4 ETAPAS
http://www.educa.madrid.org/binary/374/files714/recursos/02054/indice.html
http://www.educa.madrid.org/binary/374/files714/recursos/02063/indice.html
http://www.educa.madrid.org/binary/374/files714/recursos/02052/indice.html
http://www.educa.madrid.org/binary/374/files714/recursos/02051/indice.html