APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

BROWN, Lester R. [et al]. State of the World 1991: A Worldwatch Institute Report on Progress Toward a Sustainable Society. New York: W.W. Norton and Co, 1991.

MLA (9e ed.) Bronvermelding

BROWN, Lester R. [et al]. State of the World 1991: A Worldwatch Institute Report on Progress Toward a Sustainable Society. W.W. Norton and Co, 1991.