[1] Document Structure – SVG 1.1 (Second Edition) ( (2011-08-10 12:35:27 +09:00 版)) <http://www.w3.org/TR/2011/REC-SVG11-20110816/struct.html#UseElement>

[2] IRC logs: freenode / #whatwg / 20140106 ( (2014-01-07 23:19:33 +09:00 版)) <http://krijnhoetmer.nl/irc-logs/whatwg/20140106#l-558>

[3] Issue 313438 - chromium - Lets rip out the SVG instance tree - An open-source project to help move the web forward. - Google Project Hosting ( (2014-01-08 20:39:19 +09:00 版)) <https://code.google.com/p/chromium/issues/detail?id=313438>

[4] 508561 – SVGUseElement has no instanceRoot attribute (SVG DOM) ( (2014-01-08 20:39:40 +09:00 版)) <https://bugzilla.mozilla.org/show_bug.cgi?id=508561>

[5] Removing the SVG instance tree (SVG2 issue 51) ( (Philip Rogers 著, 2014-01-08 10:24:28 +09:00 版)) <http://lists.w3.org/Archives/Public/www-svg/2014Jan/0014.html>