"東急東横線「Q SEAT」導入、10両中2両をロング・クロス転換車両に". Mynavi News (in Japanese). Tokyu Toyoko Line "Q Seat" to be introduced, 2 out of 10 cars to use rotating transverse seating. 29 July 2022. Retrieved 30 July 2022.{{cite web}}: CS1 maint: others (link)
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Hirose, Atsushi (18 February 2019). "東急2000系改め,9020系が登場" [Tokyu 2000 series reclassified as 9020 series]. Japan Railfan Magazine Online (in Japanese). Retrieved 20 December 2021.
田園都市線および大井町線の朝ラッシュ時の混雑緩和施策を実施 [Measures implemented to alleviate morning rush-hour overcrowding on Denentoshi and Ōimachi Lines] (PDF). News release (in Japanese). Japan: Tokyu Corporation. 22 March 2017. p. 2. Archived(PDF) from the original on 23 March 2017. Retrieved 23 March 2017.
web.archive.org
田園都市線および大井町線の朝ラッシュ時の混雑緩和施策を実施 [Measures implemented to alleviate morning rush-hour overcrowding on Denentoshi and Ōimachi Lines] (PDF). News release (in Japanese). Japan: Tokyu Corporation. 22 March 2017. p. 2. Archived(PDF) from the original on 23 March 2017. Retrieved 23 March 2017.