1. W3C. (1999). Web Content Accessibility Guidelines 1.0. https://www.w3.org/TR/WCAG10/
2. W3C. (2008). Web Content Accessibility Guidelines (WCAG) 2.0. https://www.w3.org/TR/WCAG20/
3. W3C. (2020). WAI-ARIA Overview. Web Accessibility Initiative (WAI). https://www.w3.org/WAI/standards-guidelines/aria/
4. W3C. (2021, January 21). Web Content Accessibility Guidelines (WCAG) 3.0. https://www.w3.org/TR/wcag-3.0/
5. W3C. (n.d.a). Web Accessibility Initaitive. Web Accessibility Initiative (WAI). Retrieved May 8, 2021, from https://www.w3.org/WAI/