United Nations, World Urbanization Prospects: The 2007 Revision.
National Wildlife Federation
A forest bathing trip increases human natural killer activity and expression of anti-cancer proteins in female subjects.
National Recreation and Park Association
National Wildlife Federation: Be out there
New York Times: The Claim: Exposure to Plants and Parks Can Boost Immunity
Medical: Spending time outside has many health benefits
Childrenandnature – Health benefits to children from contact with the outdoors & nature
Childrenandnature – Children’s Nature Deficit: What We Know – and Don’t know
CNN – Carbon footprint of the world’s biggest cities
Spending Time in Nature Makes People Feel More Alive, Study Shows