Ward, B., & Dubos, R. (1972). Only one earth: The care and maintenance of a small planet : an unofficial report commissioned by the Secretary-General of the United Nations Conference on the Human Environment prepared with the assistance of a 152-member Committee of Corresponding Consultants in 58 countries. Harmondsworth: Penguin Books.

Ward, Barbara, and Rene Dubos. Only One Earth: The Care and Maintenance of a Small Planet : An Unofficial Report Commissioned By the Secretary-General of the United Nations Conference On the Human Environment Prepared With the Assistance of a 152-member Committee of Corresponding Consultants in 58 Countries. Harmondsworth: Penguin Books, 1972.

Ward, Barbara, and Rene Dubos. Only One Earth: The Care and Maintenance of a Small Planet : An Unofficial Report Commissioned By the Secretary-General of the United Nations Conference On the Human Environment Prepared With the Assistance of a 152-member Committee of Corresponding Consultants in 58 Countries. Harmondsworth: Penguin Books, 1972.