Cita APA (7th ed.)

KREBS, C. J. (1999). Ecological methodology.-- Ed.2. An Imprint of Addison Wesley Longman.

Cita Chicago (17th ed.)

KREBS, Charles J. Ecological Methodology.-- Ed.2. California: An Imprint of Addison Wesley Longman, 1999.

Cita MLA (9th ed.)

KREBS, Charles J. Ecological Methodology.-- Ed.2. An Imprint of Addison Wesley Longman, 1999.