[1] [CITE@ja[Common Lispと時間とタイムゾーン - octahedron]]
([TIME[2019-04-25 10:30:59 +09:00]])
<http://octahedron.hatenablog.jp/entry/2018/12/04/000031>

[2] [CITE@ja[Universal time と協定世界時(UTC) : セマンティックウェブ・ダイアリー]]
([TIME[2019-04-25 10:36:21 +09:00]])
<http://blog.livedoor.jp/s-koide/archives/2268050.html>

[3] [CITE[LOCAL-TIME :: A Common Lisp Library for Times and Dates]]
([TIME[2014-12-05 11:24:51 +09:00]])
<https://common-lisp.net/project/local-time/>

[4] [CITE[Erik Naggum — A Long, Painful History of Time]]
([[Erik Naggum]]著, [TIME[2009-05-01 13:51:31 +09:00]])
<http://naggum.no/lugm-time.html>