Weston, Anthony (1996). "Self-validating reduction: A theory of environmental devaluation". Environmental Ethics. 18: 115–132. doi:10.5840/enviroethics199618227.
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Jickling, B., Lotz-Sisitka, H., O’Donoghue, R., Ogbuigwe. A. (2006). "Environmental Education, Ethics, and Action"(PDF). United Nations Education Program (UNEP). p. 12.{{cite web}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)