1. Gigaphoton Inc., News, 17 Feb 2015, http://www.gigaphoton.com/news/
2. Optics.org, News, 21 Jan 2015, http://optics.org/news/6/1/28
3. Lifetime and refurbishment of multilayer LPP collector mirrors
4. EUV Sources for Lithography
5. Heat-Resistance of Mo/Si Multilayer EUV Mirrors with Interleaved Carbon Barrier-Layers;Takenaka,1996