東急5050系が西武鉄道池袋線で営業運転開始 [Tokyu 5050 series enters service on the Seibu Ikebukuro Line]. RM News (in Japanese). Japan: Neko Publishing. 10 September 2012. Retrieved 10 September 2012.
西武線全駅で駅ナンバリングを導入します [Station numbering to be introduced at all Seibu stations] (PDF). News Release (in Japanese). Japan: Seibu Railway. 23 February 2012. Archived from the original(PDF) on 24 September 2015. Retrieved 27 March 2013.
池袋線が東急東横線、横浜高速みなとみらい線との相互直通運転を開始します。 [Inter-running to commence between Ikebukuro Line and Tokyu Toyoko and Minatomirai Lines] (PDF). News Release (in Japanese). Seibu Railway. 24 July 2012. Archived from the original(PDF) on 13 August 2012. Retrieved 25 July 2012.
西武線全駅で駅ナンバリングを導入します [Station numbering to be introduced at all Seibu stations] (PDF). News Release (in Japanese). Japan: Seibu Railway. 23 February 2012. Archived from the original(PDF) on 24 September 2015. Retrieved 27 March 2013.
池袋線が東急東横線、横浜高速みなとみらい線との相互直通運転を開始します。 [Inter-running to commence between Ikebukuro Line and Tokyu Toyoko and Minatomirai Lines] (PDF). News Release (in Japanese). Seibu Railway. 24 July 2012. Archived from the original(PDF) on 13 August 2012. Retrieved 25 July 2012.