Gardner, D.H.
New York: Institute of Pasific Relations, 1950
Buku Teks
Chafe, William Henry
Oxford University Press, 1995
Buku Teks
Williamson, Bill
Oxford Basil Balckwell 1990,
Buku Teks
Spanier, John
Frederck A. Praeger, 1968
Buku Teks
Young, Peter
Bison Books, 1985
Buku Referensi