1. United Nations: Convention on the Rights of Persons with Disabilities - Articles (2006). http://cort.as/-GlqK
2. Shawn Lawton Henry, McGee, L.: Accessibility (2019). https://www.w3.org/standards/webdesign/accessibility
3. World Wide Web Consortium: World Wide Web Consortium Launches International Program Office for Web Accessibility Initiative (1997). https://www.w3.org/Press/IPO-announce
4. Shawn Lawton Henry: Introduction to Web Accessibility (2019). https://www.w3.org/WAI/fundamentals/accessibility-intro/
5. International Organization for Standardization: Information technology — W3C Web Content Accessibility Guidelines (WCAG) 2.0 (2012). https://www.iso.org/standard/58625.html