Johnson, George B., author
McGraw-Hill, 2003
Buku Teks
Toynbee, Arnold J., author
Oxford University Press, 1957
Buku Teks
Rosenberg, Donna
Buku Teks
Ople, Blas F. author
Institute for Public Policy, 2001
Buku Teks
Hong Jong-son, Pak Young-son, Sok Geum-ho, Umeda Hiroyuki
Pagijong Press, 2008
Buku Teks