Tower Records (http://tower.jp/) is a Japanese retailer. They have discography pages for artists as well as purchase links for releases (which are a good source for info). Since the site deals in physical media these links should autoselect to "purchase for mail-order."
Example artist URL: http://tower.jp/artist/1372640/ (shortened from http://tower.jp/artist/1372640/%E9%87%8E%E4%B8%AD-%E3%81%BE%E3%81%95-%E9%9B%84%E4%B8%80)
Example release URL: http://tower.jp/item/4458536/ (shortened from http://tower.jp/item/4458536/%E8%B6%85%E3%83%BB%E5%B0%91%E5%B9%B4%E6%8E%A2%E5%81%B5%E5%9B%A3NEO)