Brown, L. R. (1990). State of the world 1990: A worldwatch institute report on progress toward a sustainable society. New York: W. W. Norton & Company.
Παραπομπή Chicago StyleBrown, Lester R. State of the World 1990: A Worldwatch Institute Report On Progress Toward a Sustainable Society. New York: W. W. Norton & Company, 1990.
Παραπομπή MLABrown, Lester R. State of the World 1990: A Worldwatch Institute Report On Progress Toward a Sustainable Society. New York: W. W. Norton & Company, 1990.
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