[1] Styling – SVG 1.1 (Second Edition) ( (2011-08-10 12:35:27 +09:00 版)) http://www.w3.org/TR/2011/REC-SVG11-20110816/styling.html#AuralStyleSheets

[2] Styling – SVG 1.1 (Second Edition) ( (2011-08-10 12:35:27 +09:00 版)) http://www.w3.org/TR/2011/REC-SVG11-20110816/styling.html#AuralStyleSheets

[3] Fix races between tasks resolving/rejecting play promises and them be… ( (mounirlamouri著, 2016-04-13 00:57:59 +09:00)) https://github.com/whatwg/html/commit/18be384bc7c9c1a7f3201a73e870682844addf3a