Speech by Okubo Akio, 大久保明男, in Japanese; oral interview
https://www.bilibili.com/video/BV1qs411h7ea/
Okada Hideki, 冈田英树, discusses his 2019 Japanese language book in Chinese; article
https://twgreatdaily.com/zh-cn/ITkz63EBiuFnsJQV2fd5.html [backup link]