[1] メタ構文変数 - Wikipedia (2011-10-23 15:55:42 +09:00 版) http://ja.wikipedia.org/wiki/%E3%83%A1%E3%82%BF%E6%A7%8B%E6%96%87%E5%A4%89%E6%95%B0
[3] RFC 3092 - Etymology of "Foo", 2025-01-22T03:29:17.000Z https://datatracker.ietf.org/doc/html/rfc3092