1. The demographic transition: Three centuries of fundamental change;Lee;J Econ Perspect,2003
2. Colombia — Population projections of Bogotá and the major demographic indicators 2005-2020. Based on data from the 2005 National Population Census [consultado 1 Mar 2015]. Disponible en: http://www.dane.gov.co/index.php/poblacion-y-demografia/proyecciones-de-poblacion
3. DANE. Proyecciones nacionales y departamentales de población. Estudios postcensales. Vol. No. 7. 2009; ISBN 978-624-078-9.2005-2020.
4. The impact of pain management on quality of life;Katz;J Pain Symptom Manage,2002
5. Pain epidemiology and health-related quality of life in patients with chronic non-malignant pain;Becker;Ugeskr Laeger.,1998