"大阪市交御堂筋線用30000系が営業運転を開始" [Osaka Municipal Subway 30000 series begins revenue service on the Midosuji Line]. Japan Railfan Magazine Online (in Japanese). Japan: Koyusha Co., Ltd. 2011-12-11. Retrieved 2022-07-25.
"北大阪急行9000形が営業運転を開始" [Kita-Osaka Kyuko 9000 series enters revenue service]. Japan Railfan Magazine Online (in Japanese). Japan: Koyusha Co., Ltd. 2014-04-29. Retrieved 2022-07-25.