"List of Provinces". PSGC Interactive. Makati City, Philippines: National Statistical Coordination Board. Diarsipkan dari versi asli tanggal 2013-01-11. Diakses tanggal 6 February 2013.
"List of Provinces". PSGC Interactive. Makati City, Philippines: National Statistical Coordination Board. Diarsipkan dari versi asli tanggal 2013-01-11. Diakses tanggal 6 February 2013.