Yu, Yon-thae
Naenara suwil thoyo haeng : 3040 el wihan yohaeng ui hyanggi
Book I, 2007
Buku Referensi
Kim, Hye Suk
(Modorigatonanen) gugo hakkwa gugo gyohaeng : haeng sol
Wolin, 2009
Buku Teks
No, Dae Gyu
Gugo hak seaseol
Sinwonmunhwasa, 2008
Buku Teks
Hong, Sa-man
Gugo hyongtae emie tamsek
Yoklak, 2009
Buku Teks
Choi, Song Wu
Gugo-ui gosu.1-3
Communication Books, 2007
Buku Referensi