Wilson, Graham K., author
Chatham House, 1985
Buku Teks
Edwina Rosanti Badudu, author
2017
UI - Skripsi Membership
Madura, Jeff, author
South-Western College, 2001
Buku Teks
Straub, Joseph T., author
Kent, 1985
Buku Teks
Monsen, R. Joseph, author
Houghton Mifflin, 1967
Buku Teks