「とびら」の紹介 Introduction to TOBIRA 『とびら』の特徴About TOBIRA『上級へのとびら』（本冊）TOBIRA: Gateway to Advanced Japanese『きたえよう漢字力』TOBIRA: Power Up Your KANJI『これで身につく文法力』TOBIRA: Grammar Power - Exercises for Mastery『中級日本語を教える教師の手引き』TOBIRA: Teaching Intermediate Japanese - Teacher's Guide『とびら』の著者Authors
