Muccigrosso, author
Krieger publishing company, 2001
Buku Teks
Embassy of the United States of American, [date of publication not identified]
Buku Teks
Office of International Information Programs, 1991
Buku Teks
Gray, Richard, 1944-, author
John Wiley & Sons, 2015
Buku Teks
W.H. Freeman, 1982
Buku Teks