1. Geothermal heat pumps—DOE (USA), 〈http://www.eren.doe.gov〉; 2014.
2. Energy efficiency technologies—air source heat pump vs. ground source heat pump;Wu;J Sustain Dev,2009
3. Chiasson AD. Simulation and design of hybrid geothermal heat pump systems [Ph.D. thesis]. USA: University of Wyoming; 2007.
4. Glhepro: ground loop heat exchangers professional design tool, 〈http://www.hvac.okstate.edu/glhepro/〉; 2014.
5. Eskilson P. Thermal analysis of heat extraction boreholes [Ph.D. thesis]. Sweden: University of Lund; 1987.