[1] N± - Wikipedia (2016-12-29 04:39:24 +09:00) <https://ja.wikipedia.org/wiki/N%C2%B1>

[2] ±ふぃに - Wikipedia (2016-12-24 16:52:03 +09:00) <https://ja.wikipedia.org/wiki/%C2%B1%E3%81%B5%E3%81%83%E3%81%AB>

[3] ギフト± - Wikipedia (2017-03-02 14:06:02 +09:00) <https://ja.wikipedia.org/wiki/%E3%82%AE%E3%83%95%E3%83%88%C2%B1>