Middleton, N., Weston, S., & Downes, J. (1989). Atlas of environmental issues. Facts on File.
Lua i Stíl Chicago (17ú heag.)Middleton, Nick, Steve Weston, agus John Downes. Atlas of Environmental Issues. New York: Facts on File, 1989.
Lua MLA (8ú heag.)Middleton, Nick, et al. Atlas of Environmental Issues. Facts on File, 1989.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.