[1] [CITE@en[File: SPEC]]
([TIME[2009-03-25 22:25:13 +09:00]] 版)
<http://rack.rubyforge.org/doc/files/SPEC.html>

[2] [CITE@en[File: SPEC ''''''['''''''Rack Documentation''''''']'''''']]
( ([TIME[2010-01-11 00:57:50 +09:00]] 版))
<http://rack.rubyforge.org/doc/SPEC.html>