• 22 Wildlife conservation
• 20 Climatic changes
• 8 Renewable energy sources
• 4 World Wide Fund for Nature
• 2 Agriculture
• 2 Goodall, Jane, 1934-
• 2 Pollution
• 2 Transportation
• 2 Water conservation

• 40 Thomson, Andrew
• 37 Alexander Street Press
• 37 Bartlett, G. (Gillian)
• 37 Bartlett, Gillian
• 34 Thompson, Andrew
• 14 Switch International

• 74 English

• 2 Great Barrier Reef (Qld.)
• 2 Stonehenge World Heritage Site (England)

• 37 Internet videos

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