COnyango & Tolba Mostafa. (1992). The World environment 1972-1992: Two decades of challenge. Chapman & Hall.
Lua i Stíl Chicago (17ú heag.)COnyango agus Tolba Mostafa. The World Environment 1972-1992: Two Decades of Challenge. London: Chapman & Hall, 1992.
Lua MLA (9ú heag.)COnyango agus Tolba Mostafa. The World Environment 1972-1992: Two Decades of Challenge. Chapman & Hall, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.