1. Studies on solar heating systems with long-term heat storage for northern high latitudes;Lund,1984
2. Markwärme, Del I–III, Byggforskningsrådet;Claesson,1985
3. Thermal analysis of heat extraction boreholes;Eskilson,1987
4. Annual solar heat storage in the bedrock;Punttila,1983
5. Ground heat storage: Thermal analysis of duct storage systems, 1. Theory;Hellström,1987