Não informado. (1981). Environmental Education and Information. University of Salford.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Environmental Education and Information. Salford, Inglaterra: University of Salford, 1981.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Environmental Education and Information. University of Salford, 1981.
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