• 16 Videos, Slides, Films

• 14 Conservation of natural resources
• 14 Ecology
• 10 Recycling (Waste, etc.)
• 8 Endangered species
• 2 Renewable energy sources
• 2 Research
• 2 Technological innovations
• 2 Wildlife conservation
• 1 Detection
• 1 Experimental automobiles
• 1 Genetics

• 14 Holmes, Abbe
• 7 Alexander Street Press
• 2 Campbell, Craig

• 16 English

• 7 Internet videos

Limit year range