"List of Provinces". PSGC Interactive. Makati City, Philippines: National Statistical Coordination Board. Diarsipkan dari versi asli tanggal 2013-01-21. Diakses tanggal 27 March 2013.
"List of Provinces". PSGC Interactive. Makati City, Philippines: National Statistical Coordination Board. Diarsipkan dari versi asli tanggal 2013-01-21. Diakses tanggal 27 March 2013.