1. Chai Qinhu, Ma GuoYuan. State of knowledge and current challenges in the ASHP developed for the cold areas [J]. Energy Engineering, 2003,5.
2. Shen ming, Song Zhiping. Applicability of air-source heat pumps in colder climate and relevant measures [J]. Heating Ventilating & Air Conditioning, “2002”32(6): 37-39.
3. Rao Rongshui, Gu Bo, Zhou Ze, Shen Jianjun and Kong Bo. Development of Air Source Heat Pump for Cold Regions [J]. Building Energy & Environment,,2005,(04):24-28+81.
4. Yu Lihua, Ma GuoYuan, Xu Rongbao. Current Status and Development of Low Temperature Air-source Heat Pump [J]. Construction Conserves Energy, 2007,(03):54-57.
5. Ma Honglei, Ma ZhongYuan, Yue Shaoqing. Technical and Economic Analysis for Application of the New Type Air Resource Heat Pump in Cold Regions of China [J]. Construction Machinery For Hydraulic Engineering & Power Station,,2005,(03):73-75. .