[2] [CITE[MySQL のNULL ではまったことあれこれ - Slow Dance]]
([TIME[2010-03-23 09:54:42 +09:00]] 版)
<http://d.hatena.ne.jp/LukeSilvia/20100322/p1>


[3] [CITE@ja[3値論理]], [TIME[2017-07-13T15:22:18.000Z]], [TIME[2025-10-14T06:20:30.044Z]] <https://mickindex.sakura.ne.jp/database/db_3vl.html>


[1] [CITE@ja[130値論理]], [TIME[2017-08-04T14:12:56.000Z]], [TIME[2025-10-14T06:14:37.344Z]] <https://mickindex.sakura.ne.jp/database/db_130.html>