[1] Requirements for Internationalization Tag Set (ITS) 2.0 ( (2012-05-23 14:46:22 +09:00 版)) http://www.w3.org/TR/2012/WD-its2req-20120524/#Implementation_Approach

[2] Internationalization Tag Set (ITS) Version 2.0 ( (2013-10-27 19:39:43 +09:00 版)) http://www.w3.org/TR/its20/#html5-local-attributes

[3] Internationalization Tag Set (ITS) Version 2.0 ( (2013-10-27 19:39:43 +09:00 版)) http://www.w3.org/TR/its20/#its20-elements-and-attributes