Ward, B. (1972). Only the earth: The care and maintenance of a small planet. New York: Pengiun Books.
Παραπομπή Chicago StyleWard, Barbara. Only the Earth: The Care and Maintenance of a Small Planet. New York: Pengiun Books, 1972.
Παραπομπή MLAWard, Barbara. Only the Earth: The Care and Maintenance of a Small Planet. New York: Pengiun Books, 1972.
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