1. Geothermal Energy;Dickson,1995
2. Geothermal Heating: A Handbook of Engineering Economy;Harrison,1990
3. Geothermal Direct Use Engineering and Design Guidebook;Lund,1998
4. Geothermal District Energy System Analysis, Design, and Development;Bloomquist,2001
5. K. Rafferty, Selected Cost Considerations for Geothermal District Heating in Existing Single – Family Residential Areas, Quarterly Bulletin, vol. 17, No: 3, Geo-Heat Center.