APA
United Nations Conference on Trade and Development. Trade and Development Board, . (1991). Generalised system of preferences. Geneva: United Nations.
Chicago
United Nations Conference on Trade and Development. Trade and Development Board, . 1991. Generalised system of preferences. Geneva: United Nations.
Harvard
United Nations Conference on Trade and Development. Trade and Development Board, . (1991). Generalised system of preferences. Geneva: United Nations.
MLA
United Nations Conference on Trade and Development. Trade and Development Board, . Generalised system of preferences. Geneva: United Nations. 1991.