Não informado. (1970). Environmental quality. Council on Environmental Quality, Executive Office of the President.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Environmental Quality. Washington: Council on Environmental Quality, Executive Office of the President, 1970.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Environmental Quality. Council on Environmental Quality, Executive Office of the President, 1970.
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