Prentice-Hall, 1995
Buku Teks
Prentice-Hall, 2003
Buku Teks
by Greg Bounds [and others]
McGraw-Hill, 1994
Buku Teks
Tarigan, Rostiana, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2005
UI - Tesis (Membership)
McGraw-Hill, 1994
Buku Teks