2010 ADA/ABA Accessibility Guidelines
See chapter 2, Scoping.
https://www.ada.gov/regs2010/2010ADAStandards/2010ADAStandards_prt.pdf
Center for Universal Design – Principles of Universal Design
In english with guidelines
https://projects.ncsu.edu/ncsu/design/cud/about_ud/udprinciplestext.htm
In multiple languages
https://projects.ncsu.edu/ncsu/design/cud/about_ud/udnonenglishprinciples.html