1. Apple - iPad 2,
http://www.apple.com/ipad/
2. Amazon’s Original Wireless Reading Device (1st generation) Kindle Store,
http://www.amazon.com/gp/product/B000FI73MA
3. Isono, H., Takahashi, S., Takiguchi, Y., Yamada, C.: Comparison of Visual Fatigue from Reading Between Electronic Paper and Conventional Paper, The Institute of Electronics, Information and Communication Engineers, Technical Report of IECE. EID, 104(666), pp.9–12 (2005)
4. Lee, D.S., Yeh, Y.Y.: Visual fatigue for using electronic paper displays. OIT Journal 27, 105–114 (2007)
5. Kang, Y.Y., Wang, M.J.J., Lin, R.: Usability Evaluation of E-books. Displays 30, 49–52 (2009)