[1] [CITE@en[RFC 6585 - Additional HTTP Status Codes]]
( ([TIME[2012-05-03 01:56:08 +09:00]] 版))
<http://tools.ietf.org/html/rfc6585#section-6>

[2] [CITE@en[List of HTTP status codes - Wikipedia, the free encyclopedia]]
( ([TIME[2013-10-01 11:44:11 +09:00]] 版))
<http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#511>