Cita APA

Brown, L. R., Flavin, C., & Renner, M. (1997). Vital signs 1997: The environmental trends that are shaping our future. New York: Worldwatch Institute.

Citación estilo Chicago

Brown, Lester R., Christopher Flavin, y Michael Renner. Vital Signs 1997: The Environmental Trends That Are Shaping Our Future. New York: Worldwatch Institute, 1997.

Cita MLA

Brown, Lester R., Christopher Flavin, y Michael Renner. Vital Signs 1997: The Environmental Trends That Are Shaping Our Future. New York: Worldwatch Institute, 1997.