参考文献

Wang, Licai; Gao, Zhanxian; Li, Wei; Zheng, Guotong; Dong, Qingxin; Liu, Riping; Wang, Xiaohuan; Zhang, Nan; Wang, Jingzhuang; Cai, Shimian Patent: US2011/301385 A1, 2011 ; Location in patent: Page/Page column 7 ;