[1] 日本語組版処理の要件(日本語版) ( (Japanese Layout Task Force 著, 版)) http://www.w3.org/TR/jlreq/ja/#d3e857
[2] 日本語組版処理の要件(日本語版) ( (Japanese Layout Task Force 著, 版)) http://www.w3.org/TR/jlreq/ja/#ja-subheading2_7_3
[3] 日本語組版処理の要件(日本語版) ( (Japanese Layout Task Force 著, 版)) http://www.w3.org/TR/jlreq/ja/#term.even-inter-character-spacing
[4] Techniques for WCAG 2.0 ( ( 版)) http://www.w3.org/TR/2014/NOTE-WCAG20-TECHS-20140311/complete.html#F88