1. Na Zhao: The research on new process of the comprehensive treatment technology on copper wastewater (Master's thesis, China, 2009).
2. Yunlan Li, Liang Zhao, and Jing Xu, et al.: submitted to Journal of Kunming Metallurgy College (2007) in Chinese.
3. Feng Tian, Jingzhu Zhang, Weihong Shi et al.: submitted to Gansu Metallurgy (2006) in Chinese.
4. Bai He, Kanga Yong, Hongen Quan et al.: submitted to International Journal of Mineral Processing (2012).
5. Tingan Zhan, Zhihe Dou: submitted to Journal of Northeastern University (Natural Science) (2006) in Chinese.