Seok, Dong-yeon, author
Wisdom House, 2008
Buku Teks
Seok, Dong-yeon, author
Wisdom House, 2009
Buku Teks
Jong, Su-yong, author
Walaenem, 2010
Buku Teks
Eo, Thaek, author
Scola, 2009
Buku Teks
American Association of State Highway and Transportation Officials, 2008
Buku Referensi