Hawken, Paul
Little, Brown and company , 1999
Buku Teks
edited by Immanuel Lim
Discern Pub. House, 2010
Buku Teks
Cetron, Marvin J.
McGraw-Hill, 1982
Buku Teks
Gardiner, Gareth S.
Peterso's, 1996
Buku Teks
LG Kyong Je Yeongu Won
Han guk kyung je sin mun han gyung BP, 2006
Buku Teks