National Environmental Education Development. National Park Foundation. (1971). Adventure in environment: Teacher's guide. Silver Burdett.
Citazione stile Chigago Style (17a edizione)National Environmental Education Development. National Park Foundation. Adventure in Environment: Teacher's Guide. Morristown, NJ: Silver Burdett, 1971.
Citatione MLA (9a ed.)National Environmental Education Development. National Park Foundation. Adventure in Environment: Teacher's Guide. Silver Burdett, 1971.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.