[1] [CITE@en[Spatial navigation - Wikipedia, the free encyclopedia]]
( ([TIME[2013-10-29 17:05:30 +09:00]] 版))
<http://en.wikipedia.org/wiki/Spatial_navigation>

[2] [CITE@ja[ブラウザの空間ナビゲーション - snyk_s log]]
( ([TIME[2013-12-06 02:01:25 +09:00]] 版))
<http://saneyukis.hatenablog.com/entry/2013/12/04/230843>

[3] [CITE@ja[空間ナビゲーション - Opera Wiki]]
( ([TIME[2013-04-22 12:20:09 +09:00]] 版))
<http://ja.opera-wiki.com/%E7%A9%BA%E9%96%93%E3%83%8A%E3%83%93%E3%82%B2%E3%83%BC%E3%82%B7%E3%83%A7%E3%83%B3>

[4] [CITE@en-GB-hixie[Web Controls 1.0]]
( ([TIME[2004-11-08 23:49:52 +09:00]] 版))
<http://www.whatwg.org/specs/web-controls/current-work/#the-documentui>