Ruby Markup
HTML5, A vocabulary and associated APIs for HTML and XHTML, Editor's Draft 9 June 2014
W3C HTML Ruby Markup Extensions, W3C Working Group Note 04 February 2014
CSS Ruby Module Level 1, W3C Working Draft 19 September 2013
Ruby Annotation, W3C Recommendation 31 May 2001 (Markup errors corrected 25 June 2008)