1. We Are Social and Hootsuite: Digital 2019: Global Internet Use Accelerates - We Are Social.
https://wearesocial.com/blog/2019/01/digital-2019-global-internet-use-accelerates
2. World Health Organization (WHO): World report on disability.
https://www.who.int/disabilities/world_report/2011/report/en/
3. World Wide Web Consortium: Web Content Accessibility Guidelines (WCAG) 2.1.
https://www.w3.org/TR/WCAG21/
4. World Wide Web Consortium (W3C): Website Accessibility Conformance Evaluation Methodology (WCAG-EM) 1.0.
https://www.w3.org/TR/WCAG-EM/
5. Creixans-Tenas, J., Arimany-Serrat, N.: Web quality of private hospitals. In: 2016 11th Iberian Conference on Information Systems and Technologies (CISTI), pp. 1–6 (2016)