SolarCAP - http://www.solarcap.dk/

The VKR Group - http://www.vkr-holding.com/uk/vkrgruppen.htm

California Energy Commission Consumer Energy Center - http://www.consumerenergycenter.org/

California Energy Commission Renewable Energy Program - http://www.energy.ca.gov/renewables/

Database of State Incentives for Renewables & Efficiency - http://www.dsireusa.org/

European Solar Thermal Industry Federation - http://www.ESTIF.org

Solar Rating & Certification Corporation - http://www.solar-rating.org/

U.S. Department of Energy Energy Efficiency & Renewable Energy - http://www1.eere.energy.gov/solar/