『宇多田ヒカルのうた』全貌明らかに。井上陽水、椎名林檎、浜崎あゆみ、吉井和哉ら参加アーティストコメント [All details revealed for Utada Hikaru no Uta, comments from contributing artists such as Yosui Inoue, Ringo Sheena, Ayumi Hamasaki and Kazuya Yoshii.] (in Japanese). Barks. December 3, 2014. Archived from the original on March 4, 2016. Retrieved December 3, 2014.
"CDTV PowerWeb:! Utada Hikaru". Oricon (Bulletin) (in Japanese). Recording Industry Association of Japan. December 24, 2004. Archived from the original on January 21, 2007. Retrieved April 4, 2015.
"Utada – News" (in Japanese). Utada's official website (utada.jp). July 30, 2009. Archived from the original on August 10, 2009. Retrieved November 24, 2016.
utadahikaru.jp
"Passion" (in Japanese). Utada's official website (hikki.co.jp). December 14, 2005. Archived from the original on November 26, 2016. Retrieved November 24, 2016.
"Utada – News" (in Japanese). Utada's official website (utada.jp). July 30, 2009. Archived from the original on August 10, 2009. Retrieved November 24, 2016.
"CDTV PowerWeb:! Utada Hikaru". Oricon (Bulletin) (in Japanese). Recording Industry Association of Japan. December 24, 2004. Archived from the original on January 21, 2007. Retrieved April 4, 2015.
"Passion" (in Japanese). Utada's official website (hikki.co.jp). December 14, 2005. Archived from the original on November 26, 2016. Retrieved November 24, 2016.
『宇多田ヒカルのうた』全貌明らかに。井上陽水、椎名林檎、浜崎あゆみ、吉井和哉ら参加アーティストコメント [All details revealed for Utada Hikaru no Uta, comments from contributing artists such as Yosui Inoue, Ringo Sheena, Ayumi Hamasaki and Kazuya Yoshii.] (in Japanese). Barks. December 3, 2014. Archived from the original on March 4, 2016. Retrieved December 3, 2014.