Não informado. (1971). Environment information access. Environmental Information Center of Ecology Forum.
Chicago-referens (17:e uppl.)Não informado. Environment Information Access. New York: Environmental Information Center of Ecology Forum, 1971.
MLA-referens (8:e uppl.)Não informado. Environment Information Access. Environmental Information Center of Ecology Forum, 1971.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.