New York : NACLA
Majalah, Jurnal, Buletin
Washington : Pan American Union, General Secretariet of the Organization of American States
Majalah, Jurnal, Buletin
Green Press, 2003
Buku Teks
Bannon, John Francis
McGraw-Hill, 1952
Buku Teks
Oxford Business Group, [date of publication not identified]
Buku Teks