I dont really buy physical copies online, but I found this site and it looks like it has some JR vols. Or if you want to search it yourself, just copy the japanese title and google it, that way usually gives better result. Anyway here's the link:
https://search.rakuten.co.jp/search/mall/%E7%B4%94%E6%83%85%E3%83%AD%E3%83%9E%E3%83%B3%E3%83%81%E3%82%A......