Hakutaro Joo

• Gengogaku wa kagaku de aru
• Kotoba no miraigaku
• Nihongo "rashisa" no gengogaku
• Nihongo chotto ii hanashi
• Nihongo kenkyujo
• Nihonjin no Nihongo shirazu (Aruku Nihongo bukkusu)
• Tosetsu omoshiro gengogaku