Svg: Model <image xlink:href='...'> and <script xlink:href='...'> as relations.
Svg: Model style='...' as an relation.
Svg: Model <style xlink:href='...'> and <style>...</style> as relations.
Svg: Model <font-face-uri xlink:href='...'> as a relation.
Xml & Svg: Model <?xml-stylesheet href=...> as a relation.