[1] CLDR - Unicode Common Locale Data Repository http://cldr.unicode.org/
[2] ISO/IEC 10646, Universal Coded Character Set (UCS) .
[3] ISO/IEC CD 19757-7:2017, Document Schema Definition Languages (DSDL) — Part 7: Character Repertoire Description Language (CREPDL).
[4] Kyōiku kanji, Wikipedia https://en.wikipedia.org/wiki/Kyōiku_kanji
[5] The Unicode Consortium. The Unicode Standard. http://www.unicode.org/versions/latest/
[6] Unicode Standard Annex #29: Unicode Text Segmentation http://www.unicode.org/reports/tr29/
[7] Unicode Technical Standard #18: Unicode Regular Expressions http://www.unicode.org/reports/tr18/
[8] Unicode Technical Standard #35: Unicode Locale Data Markup Language (LDML) http://www.unicode.org/reports/tr35/
[9] W3C Note 14-January-2000: A Notation for Character Collections for the WWW https://www.w3.org/TR/2000/NOTE-charcol-20000114/