1. Zeng Wen and Liu Tian-mo: Nanotechnology and Precision Engineering. Vol. 7(2009), p.387.
2. ZhuJing, Wenzhi Jin: Nano Materials and Devices (Tsinghua University Press, Beijing, 2003).
3. Chuai Rong-yan, Liu Xiao-wei and Huo Ming-xue: Chinese Journal of Semiconductors. Vol. 27(2006), p.1230.
4. Lu Xue-bin, Liu Xiao-wei and Chuai Rong-yan: Advanced Materials Research. Vol. 60-61(2009), p.89.
5. J. Lindhand, M. Scharff, H. E. Schiott: Mat. Fys Med. Dan. Vid. Selsk. Vol. 33(1963), p.1.