APA
(1983). Statistical yearbook. 1981. New York: dept of International Economic and Social affairs.
Chicago
1983. Statistical yearbook. 1981. New York: dept of International Economic and Social affairs.
Harvard
(1983). Statistical yearbook. 1981. New York: dept of International Economic and Social affairs.
MLA
Statistical yearbook. 1981. New York: dept of International Economic and Social affairs. 1983.
