The following references may be useful when improving this article in the future:
- E231系近郊タイプ増備車 [Suburban E231 series expansion cars]. Japan Railfan Magazine (in Japanese). Vol. 44, no. 521. Japan: Koyusha Co., Ltd. September 2004 [segment written 17 June 2004]. pp. 85–92 – via railf-library.jp.
- E231系ファミリー [Lineup of Series E231]. Japan Railfan Magazine (in Japanese). Vol. 46, no. 539. Japan: Koyusha Co., Ltd. March 2006. pp. 8–49 – via railf-library.jp.
- E231系の誕生まで [Development for Series E231]. Japan Railfan Magazine (in Japanese). Vol. 46, no. 539. Japan: Koyusha Co., Ltd. March 2006. pp. 52–55 – via railf-library.jp.
- E231系のディテール [Details of Series E231]. Japan Railfan Magazine (in Japanese). Vol. 46, no. 539. Japan: Koyusha Co., Ltd. March 2006. pp. 56–61 – via railf-library.jp.
- E231系仕様比較 [Specifications of Series E231]. Japan Railfan Magazine (in Japanese). Vol. 46, no. 539. Japan: Koyusha Co., Ltd. March 2006. p. 62 – via railf-library.jp.
- E231系のこれから [Series E231 for the Future]. Japan Railfan Magazine (in Japanese). Vol. 46, no. 539. Japan: Koyusha Co., Ltd. March 2006. p. 63 – via railf-library.jp.