Crawfurd, John
Oxford University Press, 1971
Buku Referensi
New York : The Far Eastern Assocation, Inc
Majalah, Jurnal, Buletin
Kuiter, Rudie H.
Gramedia, 1992
Buku Referensi
Chabot, H. Th.
KITLV Press, 1996
Buku Teks SO
Maslow, Abraham H.
Harper & Row, 1966
Buku Teks SO