National Environmental Education Development. National Park Foundation. (1971). Adventure in environment: Teacher's guide. Silver Burdett.
Chicago-Zitierstil (17. Ausg.)National Environmental Education Development. National Park Foundation. Adventure in Environment: Teacher's Guide. Morristown, NJ: Silver Burdett, 1971.
MLA-Zitierstil (9. Ausg.)National Environmental Education Development. National Park Foundation. Adventure in Environment: Teacher's Guide. Silver Burdett, 1971.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.