"List of Provinces". PSGC Interactive. Makati City, Philippines: National Statistical Coordination Board. Diarsipkan dari versi asli tanggal 2013-01-11. Diakses tanggal 20 December 2013.
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"List of Provinces". PSGC Interactive. Makati City, Philippines: National Statistical Coordination Board. Diarsipkan dari versi asli tanggal 2013-01-11. Diakses tanggal 20 December 2013.