Puente, D., Zabaleta, E., Rodríguez-Blanco, T., Cabanas, M., Monteagudo, M., Pueyo, M.J., … Bolíbar, B. (2011).Gender differences in sexual risk behaviour among adolescents in Catalonia, Spain. Gaceta Sanitaria, 25(1),13–19. doi: 10.1016/j.gaceta.2010.07.012