You can find a YouTube video news report on the linked page. You can also hear the audio of a Montana Public Radio segment about the event here:

http://mtpr.org/post/montana-celebrates-35th-anniversary-japanese-sister-state

Finally, here’s a newspaper article:

http://missoulian.com/news/local/japan-friends-gather-to-celebrate-kumamoto-sister-state/article_922a90ca-7936-544c-8fd3-a363fed2a2a0.html

– KIrk

http://www.kxlf.com/story/36855432/kumamoto-and-montana-celebrate-sister-state-status