Hardware Bible, Sixth Edition 著者: Winn L. Rosch 733 ページ
http://books.google.com/books?id=S90OaKQ-IzMC&pg=PA733&vq=relationship&as_brr=3&hl=ja&source=gbs_search_r&cad=1_1because the arrangement of the type bars has no direct relationship to the arrangement of keys.