https://sites.google.com/site/catala4t/la-s-sonora-i-la-s-sorda
http://psicoreeduca.wordpress.com/2012/10/09/normes-ortografiques-rrr-essa-sordaessa-sonora/http://www2.vedruna-angels.org/vangels/antiga/clicsprim/4/ssordaisonora2.htm

http://www.editorialteide.es/elearning/Primaria.asp?IdJuego=1594&IdTipoJuego=8