Não informado. (1981). Environmental Education and Information. University of Salford.
Chicago-referens (17:e uppl.)Não informado. Environmental Education and Information. Salford, Inglaterra: University of Salford, 1981.
MLA-referens (8:e uppl.)Não informado. Environmental Education and Information. University of Salford, 1981.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.