APA引文

Perera, P. (1989). Emerging issues of population aging in Sri Lanka. United Nations.

Chicago Style (17th ed.) Citation

Perera, P.D.A. Emerging Issues of Population Aging in Sri Lanka. New York: United Nations, 1989.

MLA引文

Perera, P.D.A. Emerging Issues of Population Aging in Sri Lanka. United Nations, 1989.