Cauley, Troy Jesse
International Textbook, Co., 1968
Buku Teks
US. Department of State, 2005
Multimedia
Ulfa Sarah Dina, author
2018
UI - Makalah dan Kertas Kerja
US. Department of State, 2005
Multimedia
Dewhurst, J. Frederic, author
Twentieth Century Fund, 1955
Buku Teks