http://www.taringa.net/posts/arte/3329448/Charol--Espejo--Alberto-Alabi.html

http://www.editorial.unca.edu.ar/Publicacione%20on%20line/CIENCIA%20Y%20TECNOLOGIA/Rev.%20CyT%20PDF/RevCyT10/HUMANIDADES/REYES%20-%20MELO.pdf