Center for Livable Communities

http://www.lgc.org/center/

New Urbanism

http://www.cnu.org/

International Society of Arboriculture

http://www.isa-arbor.com/

Smart Growth

http://www.smartgrowth.org/

Urban Advantage

http://www.urban-advantage.com/index.html

Visualizing Density

http://www.lincolninst.edu/subcenters/visualizing-density/

Community Development Blog

http://www.useful-community-development.org/