[1] [CITE['''['''html5''']''' r4351 - '''['''acgiowt''']''' (0) Make itemid='' accept relative URLs.]]
([TIME[2009-10-28 03:57:21 +09:00]] 版)
<http://lists.whatwg.org/pipermail/commit-watchers-whatwg.org/2009/003512.html>

[2] [CITE[''''''[''''''whatwg'''''']'''''' Proposal: allow itemid to record multiple identifiers for an item]]
( ([TIME[2012-12-05 04:18:56 +09:00]] 版))
<http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2012-December/038257.html>