http://www.mybrowserbar.com/cgi/errors.cgi?q=http%3A%2F%2Fredalyc%2Euaemex%2Emx%2Fsrc%2Finicio%2FArtPdfRed%2Ejsp%3FiCve%3D64408012&type=dns&ISN=5AA9A97235334E17A8101AF874B57D3E&ccv=130&cnid=971163&cco=US&ct=11
http://www.jornada.unam.mx/2010/04/06/index.php?section=politica&article=009n1pol
http://www.ipicyt.edu.mx/espanol/noticias/noticias.php?noticia=1511
http://www.provincia.com.mx/02-05-2010/38900