www.heatpumpcentre.org - IEA Heat Pump Centre
www.ehpa.org - European Heat Pump Association
www.soundgt.com - Ground Source Heat Pumps
www.heatpumpnet.org.uk - UK Information Network for Heat Pumps
www.earthenergy.ca - Earth Energy Society of Canada
www.retscreen.net - RETScreen International Centrum Wsparcia w zakresie Czystej Energii - Canada
