Citazione Stile APA (7a Edizione)

Brown, L. R. (1991). State of the world 1991: A worldwatch institute report on progress toward a sustainable society. W.W. Norton & Co..

Citazione stile Chigago Style (17a edizione)

Brown, Lester R. State of the World 1991: A Worldwatch Institute Report on Progress Toward a Sustainable Society. New York: W.W. Norton & Co., 1991.

Citatione MLA (9a ed.)

Brown, Lester R. State of the World 1991: A Worldwatch Institute Report on Progress Toward a Sustainable Society. W.W. Norton & Co., 1991.