* 仕様書

- [1] [CITE@en-us[UAX #44: Unicode Character Database]] ([TIME[2010-10-09 06:36:55 +09:00]] 版) <http://www.unicode.org/reports/tr44/#Noncharacter_Code_Point>
- [2] [CITE@en-us[UAX #44: Unicode Character Database]], [TIME[2020-03-06T22:23:11.000Z]], [TIME[2020-10-21T08:49:23.551Z]] <https://www.unicode.org/reports/tr44/#Property_Invariants>