1. CBD-180 ground temperatures, National Research Council Canada;Williams,1976
2. Measurements of temperature distribution in ground;Popiel;Experimental Thermal and Fluid Science,2001
3. Experimental study of a closed loop vertical ground source heat pump systems;Hepbasli;Energy Conversions and Management,2003
4. Temperatures in the Kiowa Drill Hole;Kelley,2005
5. Florides G., Kalogirou S. Annual ground temperature measurements at various depths. In: 8th REHVA World Congress, Clima, Lausanne; 2005.