Satoshi, Asa (October 5, 2018). "プロ野球におけるプレーオフの歴史。パ・リーグには幻の制度があった" [History of the playoffs in professional baseball. There was a strange system in the Pa League.]. Sportiva (in Japanese). Shueisha. Retrieved June 14, 2020.
Satoshi, Asa (October 5, 2018). "プロ野球におけるプレーオフの歴史。パ・リーグには幻の制度があった" [History of the playoffs in professional baseball. There was a strange system in the Pa League.]. Sportiva (in Japanese). Shueisha. Retrieved June 10, 2020.