Dyfyniad APA

Middleton, N., Weston, S., & Downes, J. (1989). Atlas of environmental issues. Facts on File.

Dyfyniad Arddull Chicago

Middleton, Nick, Steve Weston, and John Downes. Atlas of Environmental Issues. New York: Facts on File, 1989.

Dyfyniad MLA

Middleton, Nick, et al. Atlas of Environmental Issues. Facts on File, 1989.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.