1. Algorithms Contrast Ratio or Contrast/Brightness Difference. http://gmazzocato.altervista.org/colorwheel/. Algorithms Contrast Ratio or Contrast/Brightness Difference. http://gmazzocato.altervista.org/colorwheel/.
2. CAN Developer Accessibility Tool. https://chrome.google.com/webstore/detail/developer-accessibility-t/fcngonjbamdeknokaghjgdgkbgcdahdl. CAN Developer Accessibility Tool. https://chrome.google.com/webstore/detail/developer-accessibility-t/fcngonjbamdeknokaghjgdgkbgcdahdl.
3. CAN End User Tool - Enhance Web Page Accessibility. https://chrome.google.com/webstore/detail/enhance-web-page-accessib/mceoeijcofnglhhnanfinbemamafooma. CAN End User Tool - Enhance Web Page Accessibility. https://chrome.google.com/webstore/detail/enhance-web-page-accessib/mceoeijcofnglhhnanfinbemamafooma.
4. Cloud4all. http://cloud4all.info. Cloud4all. http://cloud4all.info.
5. Colorblind population. http://www.colorblindness.com/2006/04/28/colorblind-population. Colorblind population. http://www.colorblindness.com/2006/04/28/colorblind-population.