2Singh NP, Mccoy MT, Tice RR, et al.A simple technique for quantitation of low level of DNA damage in individual cell[J]. Exp Res,1988, 175 : 174.
3Maalouf S, El - Sabban M, Darwiche N, et al. Protective effect of vitamin E on ultraviolet B light - induced damage in keratinocytes[J]. Mol Carcinog, 2002, 34(3) : 121 - 130.