[1] XForms 1.1 (2009-10-20 22:51:54 +09:00 版) <http://www.w3.org/TR/2009/REC-xforms-20091020/#fn-if>

[2] draft-ietf-core-link-format-14 - CoRE Link Format ( (2012-06-05 06:03:10 +09:00 版)) <http://tools.ietf.org/html/draft-ietf-core-link-format-14#section-3.2>