Usui, H. (2011). Ikkai de gokaku nihongo noryoku shiken n1 bunpo taisaku (First edition.). Takahashishoten.
Dyfyniad Arddull ChicagoUsui, Hiromi. Ikkai De Gokaku Nihongo Noryoku Shiken N1 Bunpo Taisaku. First edition. Tokyo: Takahashishoten, 2011.
Dyfyniad MLAUsui, Hiromi. Ikkai De Gokaku Nihongo Noryoku Shiken N1 Bunpo Taisaku. First edition. Takahashishoten, 2011.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.