Brown, L. R. (1989). State of the world 1989: A worldwatch institute report on progress toward a sustainable society. W.W. Norton & Co..
Tohutoru Kātū Chicago (17th ed.)Brown, Lester R. State of the World 1989: A Worldwatch Institute Report on Progress Toward a Sustainable Society. New York: W.W. Norton & Co., 1989.
Tohutoro MLA (9th ed.)Brown, Lester R. State of the World 1989: A Worldwatch Institute Report on Progress Toward a Sustainable Society. W.W. Norton & Co., 1989.
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