Porritt, J., Gee, D., & Winn, C. (1990). Friends of the Earth handbook (New ed.). Macdonald.
Lua i Stíl Chicago (17ú heag.)Porritt, Jonathan, David Gee, agus Chris Winn. Friends of the Earth Handbook. New ed. London: Macdonald, 1990.
Lua MLA (9ú heag.)Porritt, Jonathan, et al. Friends of the Earth Handbook. New ed. Macdonald, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.