Não informado. (1969). Environmental Health. Environmental Health Officers Association.
Lua i Stíl Chicago (17ú heag.)Não informado. Environmental Health. London: Environmental Health Officers Association, 1969.
Lua MLA (8ú heag.)Não informado. Environmental Health. Environmental Health Officers Association, 1969.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.