Reinfeld, Fred
Sterling, 1954
Buku Teks
Asahi Shimbun Publishing, 1965
Buku Referensi
Artikel Jurnal
Clark, Michael
Prentice-Hall, 1995
Buku Teks SO
Won-young, Kim ; Hwi-joon, Ahn ; Lena, Kim ; Byong-sam, Han ; Yang-mo, Chung ; edited by. Whitfield, Roderick ; Young-sook, Pak
Jebyong Publications , 1986
Buku Referensi