@article{Wu_2018,
title={Progress in ground-source heat pumps using natural refrigerants},
volume={92},
ISSN={0140-7007},
url={http://dx.doi.org/10.1016/j.ijrefrig.2018.05.028},
DOI={10.1016/j.ijrefrig.2018.05.028},
journal={International Journal of Refrigeration},
publisher={Elsevier BV},
author={Wu,
Wei and Skye,
Harrison M.},
year={2018},
month=aug,
pages={70–85} }