Central Intelligence Agency. East & Southeast Asia :: Philippines. The World Factbook. Washington, DC: Author. 2009-10-28 [2009-11-07]. (原始内容存档于2015-07-19).
Central Intelligence Agency. East & Southeast Asia :: Philippines. The World Factbook. Washington, DC: Author. 2009-10-28 [2009-11-07]. (原始内容存档于2015-07-19).