Council on Environmental Quality (U.S.). (1990). Environmental quality: The twenty-first annual report of the Council on Environmental Quality together with The President's Message to Congress. Superintendent of Documents, U.S. Government Printing Office.
Παραπομπή σε μορφή Chicago (17η εκδ.)Council on Environmental Quality (U.S.). Environmental Quality: The Twenty-first Annual Report of the Council on Environmental Quality Together with The President's Message to Congress. Washington: Superintendent of Documents, U.S. Government Printing Office, 1990.
Παραπομπή σε μορφή MLA (9th εκδ.)Council on Environmental Quality (U.S.). Environmental Quality: The Twenty-first Annual Report of the Council on Environmental Quality Together with The President's Message to Congress. Superintendent of Documents, U.S. Government Printing Office, 1990.