Combination of borehole heat exchangers and air sparging to increase geothermal efficiency Grabe, Jürgen Menzel, Frauke Ma, Xiaolong 2013 - TUHH Open Research
Zur thermisch-hydraulisch-mechanisch gekoppelten Simulation eines Energiepfahls [Thermo-hydro-mechanical coupeld simulation of an energy pile] Ma, Xiaolong Qiu, Gang Grabe, Jürgen 2011 - TUHH Open Research