[1] [CITE@en[Terrestrial Time - Wikipedia, the free encyclopedia]] ([TIME[2016-09-07 02:21:55 +09:00]]) <https://en.wikipedia.org/wiki/Terrestrial_Time>

[2] [CITE@ja[国際原子時 - Wikipedia]]
([TIME[2017-01-14 21:10:59 +09:00]])
<https://ja.wikipedia.org/wiki/%E5%9B%BD%E9%9A%9B%E5%8E%9F%E5%AD%90%E6%99%82>