[1] draft-fielding-http-key-02 - The Key HTTP Response Header Field ( (2013-09-29 17:30:37 +09:00 版)) <http://tools.ietf.org/html/draft-fielding-http-key-02>

[2] The Key HTTP Response Header Field (2016-04-06 02:26:28 +09:00 版) <http://httpwg.org/http-extensions/key.html>