Não informado. (1990). Environmental Technology. Selper Publications.
Lua i Stíl Chicago (17ú heag.)Não informado. Environmental Technology. London: Selper Publications, 1990.
Lua MLA (8ú heag.)Não informado. Environmental Technology. Selper Publications, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.