[1] [CITE@en[List of HTTP status codes - Wikipedia, the free encyclopedia]]
( ([TIME[2012-02-19 13:30:55 +09:00]] 版))
<http://en.wikipedia.org/wiki/List_of_HTTP_status_codes>

[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#499>

[3] 
[PRE(HTTP code)[
HTTP/1.1 499 Client Disconnected
Connection: keep-alive
Server: Cowboy
]PRE]