[1] IRI 参照referenceは、 URI参照の IRI 版です。

[2] Introduction – SVG Tiny 1.2 (2008-12-20 02:31:29 +09:00 版) http://www.w3.org/TR/2008/REC-SVGTiny12-20081222/intro.html#TermIRIReference

IRI reference

An IRI reference is an Internationalized Resource Identifier with an optional fragment identifier, as defined in Internationalized Resource Identifiers [RFC3987]. An IRI reference serves as a reference to a resource or (with a fragment identifier) to a secondary resource. See References.

[3] Introduction – SVG 1.1 (Second Edition) ( (2011-08-10 12:35:27 +09:00 版)) http://www.w3.org/TR/2011/REC-SVG11-20110816/intro.html#TermIRIReference