Cita APA (7th ed.)

Brown, L. R. (1989). State of the world 1989: A worldwatch institute report on progress toward a sustainable society. W.W. Norton & Co..

Cita Chicago (17th ed.)

Brown, Lester R. State of the World 1989: A Worldwatch Institute Report on Progress Toward a Sustainable Society. New York: W.W. Norton & Co., 1989.

Cita MLA (9th ed.)

Brown, Lester R. State of the World 1989: A Worldwatch Institute Report on Progress Toward a Sustainable Society. W.W. Norton & Co., 1989.

Atenció: Aquestes cites poden no estar 100% correctes.