橘芹那さんの考え方
https://books.google.co.jp/books?id=mr4_DwAAQBAJ&;pg=PT30&lpg=PT30&dq=%E5%A5%B3%E8%A3%85+%E3%83%8E%E3%83%B3%E3%82%B1&source=bl&ots=dnoT6Ts1ZW&sig=kfQrarH5lNDvTP7SqY8Q764it50&hl=ja&sa=X&ved=0ahUKEwiho5aausPYAhVLp5QKHUySDtYQ6AEIFjAE#v=onepage&q=%E5%A5%B3%E8%A3%85%20%E3%83%8E%E3%83%B3%E3%82%B1&f=false