Não informado. (1969). Environmental Health. Environmental Health Officers Association.
Chicago-referens (17:e uppl.)Não informado. Environmental Health. London: Environmental Health Officers Association, 1969.
MLA-referens (8:e uppl.)Não informado. Environmental Health. Environmental Health Officers Association, 1969.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.