札幌市交通局、東豊線新型車両9000形の外観を公開 - デビューは2015年4月頃 [Sapporo City Transportation Bureau unveils new 9000 series trains for Toho Line - Debuting around April 2015]. Mynavi News (in Japanese). Japan: Mynavi Corporation. 4 November 2014. Retrieved 5 November 2014.
railf.jp
札幌市営地下鉄東豊線で9000形が営業運転を開始 [9000 series enters service on Sapporo Municipal Subway Toho Line]. Japan Railfan Magazine Online (in Japanese). Japan: Koyusha Co., Ltd. 9 May 2015. Retrieved 9 May 2015.
response.jp
札幌市営地下鉄東豊線の7000形がラストラン…6月25日 [Sapporo Municipal Subway Toho Line 7000 series to make final run on 25 June]. Response (in Japanese). Japan: IID Inc. 14 June 2016. Archived from the original on 26 February 2017. Retrieved 26 February 2017.
sapporo.jp
city.sapporo.jp
"地下鉄(高速電車)の概要" [Overview of the subway (high-speed train)]. city.sapporo.jp (in Japanese). Archived from the original on 19 January 2024. Retrieved 6 February 2024.
web.archive.org
札幌市営地下鉄東豊線の7000形がラストラン…6月25日 [Sapporo Municipal Subway Toho Line 7000 series to make final run on 25 June]. Response (in Japanese). Japan: IID Inc. 14 June 2016. Archived from the original on 26 February 2017. Retrieved 26 February 2017.
"地下鉄(高速電車)の概要" [Overview of the subway (high-speed train)]. city.sapporo.jp (in Japanese). Archived from the original on 19 January 2024. Retrieved 6 February 2024.