[1] ISO 6709 - Wikipedia (2020-02-19 09:21:44 +09:00) https://en.wikipedia.org/wiki/ISO_6709

[2] ISO 6709 - Wikipedia (2020-02-15 04:42:14 +09:00) https://ja.wikipedia.org/wiki/ISO_6709

[3] KS X ISO 6709:2008