* 仕様書
[REFS[
- [1] [CITE[The SMIL 3.0 Linking Modules]] ([TIME[2008-12-02 00:45:09 +09:00]] 版) <http://www.w3.org/TR/2008/REC-SMIL3-20081201/smil-extended-linking.html#adef-external>
]REFS]