引用・参考資料等 https://www.quora.com/Did-your-tank-have-a-tank-telephone-installed-If-so-where-was-it-located-Was-it-usedhttps://books.google.co.jp/books?id=sSwnj9Sf5fEC&dq=%22tank+phone%22&pg=PA43&redir_esc=y#v=onepage&q=%22tank%20phone%22&f=false
http://www.nicovideo.jp/watch/sm44220266
