[1] Accessibility Conformance Testing (ACT) Rules Format 1.0 (2017-04-05 03:57:15 +09:00) https://www.w3.org/TR/act-rules-format/

[2] Accessibility Conformance Testing (ACT) Rules Format 1.0 (2017-09-08 22:10:13 +09:00) https://www.w3.org/TR/2017/WD-act-rules-format-1.0-20170912/

[3] Accessibility Conformance Testing (ACT) Rules Format 1.0 (2018-03-06 22:49:13 +09:00) https://www.w3.org/TR/2018/WD-act-rules-format-1.0-20180308/