1. VDI Thermische Nutzung des Untergrundes – Richtlinie VDI 4640 Blatt 1 (2000), 2 (2001), 3 (2001), 4 (2004).
2. Thermal Analysis of Heat Extraction Boreholes, Doctoral Dissertation;Eskilson,1987
3. Ground Heat Storage Analyses of Duct Storage Systems—I. Theory;Hellström,1991
4. Simulation of vertical U-tube ground-coupled heat pump systems using the cylindrical heat source solution;Deerman;ASHRAE Transactions,1991
5. Design/data Manual for Closed-loop Ground Coupled Heat Pump Systems;Bose,1985