RECURSOS
1, 2 y 3. http://www.opera-europa.org/es/recursos-de-pera/qu-es-la-pera
4. https://www.youtube.com/watch?v=M7DUXmk42n8
5. https://www.youtube.com/watch?v=50mgt-Dwbbs
6. https://arteescenicas.wordpress.com/2010/05/06/la-opera-siglo-xviii-romanticismo-y-siglo-xx/
8. http://www.upf.edu/pdi/dcom/xavierberenguer/recursos/fig_calc/_6_/estampes/3_1.htm
9. https://arteescenicas.wordpress.com/2010/05/03/la-opera-i/