Referencias Bibliográficas

http://datos.bancomundial.org/pais/canada?display=graph http://www.statcan.gc.ca/start-debut-eng.html http://www.unicef.org/spanish/infobycountry/canada_statistics.html

http://www.studyincanada.com/spanish/geninfo/history.asp

http://datos.bancomundial.org/pais/colombia http://www.dane.gov.co/reloj/reloj_animado.php

http://www.unicef.org/spanish/infobycountry/colombia_statistics.html

http://datos.bancomundial.org/pais/espana?display=graph

http://www.unicef.org/spanish/infobycountry/spain_statistics.html