1. Pearson G L, Fuller C S: Proc. IRE Vol. 42 (1954), p.760.
2. ZG Chen, GX Ma, MH Tang: Materials Review 24(15) (2010), pp.122-125.
3. Q Liu: Doctor thesis, Shanghai Normal University, (2012).
4. YH Li, AB Ma, KX Zhang: Materials Review 28(3) (2014), pp.136-139.
5. Osborne M. : PV-Tech. Apr, (2010).