1. B.C. Langley, Heat Pump Technology, third ed., Prentice-Hall, Upper Saddle River, NY, 2002, ISBN 0130339652.
2. Heating and Cooling With a Heat Pump, Canada Office of Energy Efficiency, January 2000, ISBN 0661186340.
3. B. Sanner, Ground Heat Sources for Heat Pumps, International Summer School on Direct Application of Geothermal Energy, Bad Urach, 2001.
4. E. Rohner, Material, Construction and Installation of Borehole Heat Exchangers, International Summer School on Direct Application of Geothermal Energy, Bad Urach, 2001.
5. Torsional vibrations at guide-vane shaft of pump-turbine model;Predin;Shock and Vibration,1977