Linker om grunnvarme
International Ground Source Heat Pump Association
GEOexchange Information Center
Energy Efficiency and Renewable Energy Network (EREN)
International Geothermal Association
Swiss DHM. Deep Heat Mining: friendly energy from the earths interior
Australia's Hot Dry Rock (HDR) Geothermal Energy Research
U.S. Department of Energy. Geothermal Energy Technical Site
Hot Dry Rock (HDR) Geothermal Energy Research in Europe Geothermal Resources Concil