Cita APA (7th ed.)
Hickman, G. C., & Hickman, S. M. The Ecology Action Guide. Benjamin Cummings.
Cita Chicago (17th ed.)
Hickman, Graham C., i Susan M. Hickman. The Ecology Action Guide. San Francisco, EUA: Benjamin Cummings.
Cita MLA (9th ed.)
Hickman, Graham C., i Susan M. Hickman. The Ecology Action Guide. Benjamin Cummings.
Atenció: Aquestes cites poden no estar 100% correctes.