1. Sistema Nacional de Información en Salud. 2005. Disponible en: http://sinais.salud.gob.mx.
2. Gastrointestinal cancer in four medical centers in Mexico City. A 25-year study;Villalobos-Perez;Rev Gastroenterol Mex,2006
3. World Health Research;World Health Organization,2004
4. AJCC Cancer Staging Manual;Edge,2010
5. WHO classification of tumors of the digestive system;Bosman,2010