Heimlich, J. E. (2002). Environmental education: A resource handbook. Phi Delta Kappa EducationalFoundation.
Chicago-čujuhus (17. p.)Heimlich, Joe E. Environmental Education: A Resource Handbook. Estados Unidos: Phi Delta Kappa EducationalFoundation, 2002.
MLA-čujuhus (9. p.)Heimlich, Joe E. Environmental Education: A Resource Handbook. Phi Delta Kappa EducationalFoundation, 2002.
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