1. National Health Systems of the World, vol 1;Roemer,1991
2. Buku Tahunan Perangkaan 1993. Kuala Lumpur: Jabatan Perangkaan Malaysia, 1993:286–288.
3. Federation of Malaya. Annual Report 1957. Kuala Lumpur: Government Printer, 1958:290–291.
4. Raja Ahmad Noordin Raja Shahbuddin, Martinez EJ. Our Health Services in the Seventies. Kuala Lumpur: Ministry of Health Malaysia, 1977:3.