https://gigazine.net/news/20171031-asteroid-comet-beyond-solar-system/

http://kounomaki.blog84.fc2.com/blog-entry-1049.html

http://www.moj.go.jp/content/001239158.pdf

https://www.nikkei.com/article/DGXMZO22994640R01C17A1AC8000/

http://www.okinawatimes.co.jp/articles/-/165429