Παραπομπή APA

Callenbach Ernest. (1999). Ecology: A pocket guide. University Press.

Παραπομπή Chicago Style

Callenbach Ernest. Ecology: A Pocket Guide. Hyderabad: University Press, 1999.

Παραπομπή MLA

Callenbach Ernest. Ecology: A Pocket Guide. University Press, 1999.