United Nations. (1964). Studie in long term eco. projections. U.N.
Dyfyniad Arddull ChicagoUnited Nations. Studie in Long Term Eco. Projections. New York: U.N, 1964.
Dyfyniad MLAUnited Nations. Studie in Long Term Eco. Projections. U.N, 1964.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.