NHK News, 29 March 2019: 41道府県議選 無投票当選者が過去最多Archived 29 March 2019 at the Wayback Machine ("41 prefectural assembly elections: number of walkovers at all-time high"), retrieved 30 March 2019.
Ministry of Internal Affairs and Communications: 衆議院小選挙区の区割りの改定等について ("On the changes to House of Representatives single-member districts" [but covers the changes to proportional districts, too]) (in Japanese)
Ministry of Internal Affairs and Communications, 27 December 2019: Voter statistics as of September 2, 2016 [covers districts of both houses of the National Diet], p.16 (in Japanese)
NHK News, 29 March 2019: 41道府県議選 無投票当選者が過去最多Archived 29 March 2019 at the Wayback Machine ("41 prefectural assembly elections: number of walkovers at all-time high"), retrieved 30 March 2019.
wikipedia.org
ja.wikipedia.org
"按分票". Asahi Shimbun Chiezō (知恵蔵, (ja)) (in Japanese). kotobank.jp (Voyage Marketing). 21 July 2019. Retrieved 17 May 2021.