[1] [CITE[''''''[''''''whatwg'''''']'''''' Outline style to use for drawSystemFocusRing]]
( ([TIME[2013-07-27 06:52:19 +09:00]] 版))
<http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2013-July/040255.html>

[2] [CITE[''''''[''''''whatwg'''''']'''''' Outline style to use for drawSystemFocusRing]]
( ([TIME[2013-09-10 23:35:02 +09:00]] 版))
<http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2013-September/040764.html>

[3] [CITE[''''''[''''''whatwg'''''']'''''' Outline style to use for drawSystemFocusRing]]
( ([TIME[2013-10-16 20:36:49 +09:00]] 版))
<http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2013-October/041134.html>

[4] [CITE[IRC logs: freenode / #whatwg / 20140122]]
( ([TIME[2014-01-24 19:49:50 +09:00]] 版))
<http://krijnhoetmer.nl/irc-logs/whatwg/20140122>