[1] IRC logs: freenode / #whatwg / 20110412 ( (2011-04-16 19:46:57 +09:00 版)) <http://krijnhoetmer.nl/irc-logs/whatwg/20110412>
[2] Web Applications 1.0 r7230 Mention that 'direction' is supposed to affect <input type=range> ( (2012-08-10 01:45:00 +09:00 版)) <http://html5.org/tools/web-apps-tracker?from=7229&to=7230>