Filho, W. L., Palmer, J. A., & Leal, F. W. (1992). Key issues in environmental education. The Horton Print Group.
Chicago-viite (17. p.)Filho, Walter Leal, Joy A. Palmer, ja Filho Water Leal. Key Issues in Environmental Education. [England]: The Horton Print Group, 1992.
MLA-viite (9. p.)Filho, Walter Leal, et al. Key Issues in Environmental Education. The Horton Print Group, 1992.
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