URLs

• https://ja.wikipedia.org/wiki/菅野宏紀
• https://anidb.net/creator/2284
• https://www.animenewsnetwork.com/encyclopedia/people.php?id=10234
• http://www7.atwiki.jp/anime_wiki/pages/308.html
• http://www18.atwiki.jp/sakuga/pages/612.html