1. ASEAN. Retrieved from http://www.aseansec.org/64.htm
2. CIA- The World Factbook – Indonesia. Retrieved from https://www.cia.gov/library/publications/the-world-factbook/geos/id.html
3. CIA- The World Factbook – Malaysia. Retrieved from https://www.cia.gov/library/publications/the-world-factbook/geos/my.html
4. CIA- The World Factbook – Philippines. Retrieved from https://www.cia.gov/library/publications/the-world-factbook/geos/rp.html
5. CIA- The World Factbook – Singapore. Retrieved from https://www.cia.gov/library/publications/the-world-factbook/geos/sn.html