Alexander, S., & Alexander, K. (2006). Crop circles: Signs, wonders and mysteries. Chartwell Books.
Cita Chicago Style (17a ed.)Alexander, Steve, y Karen Alexander. Crop Circles: Signs, Wonders and Mysteries. London: Chartwell Books, 2006.
Cita MLA (8a ed.)Alexander, Steve, y Karen Alexander. Crop Circles: Signs, Wonders and Mysteries. Chartwell Books, 2006.
Precaución: Estas citas no son 100% exactas.