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Dyfyniad Arddull ChicagoSmith, Laurence C. The World in 2050: Four Forces Shaping Civilization's Northern Future. New York: Dutton ; Penguin, 2011.
Dyfyniad MLASmith, Laurence C. The World in 2050: Four Forces Shaping Civilization's Northern Future. Dutton ; Penguin, 2011.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.