Cita APA (7th ed.)

CALLENBACH; ERNEST. (2004). ECOLOGY - A POCKET GUIDE (REPRINT.). UNIVERSITIES PRESS.

Cita Chicago (17th ed.)

CALLENBACH; ERNEST. ECOLOGY - A POCKET GUIDE. REPRINT. HYDERABAD: UNIVERSITIES PRESS, 2004.

Cita MLA (9th ed.)

CALLENBACH; ERNEST. ECOLOGY - A POCKET GUIDE. REPRINT. UNIVERSITIES PRESS, 2004.