APA aipamena

Eckholm, E. P. (1978). Disappearing species: The social challenge. Worldwatch Institute.

Chicago Style aipamena

Eckholm, Erik P. Disappearing Species: The Social Challenge. [Washington]: Worldwatch Institute, 1978.

MLA aipamena

Eckholm, Erik P. Disappearing Species: The Social Challenge. Worldwatch Institute, 1978.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.