Heinz GaÌ?rtner, Adrian Hyde-Price, Erich Reite, editor
Lynne Rienner Publishers, 2000
Buku Teks
Black, Wendy
PBC International, 1994
Buku Referensi
Heinz GaÌ?rtner, Adrian Hyde-Price, Erich Reiter
Lynne Rienner Publishers, 2001
Buku Teks
Wood, Anthony, 1923-, author
Longman, 1983
Buku Teks
Jackson, J. Hampden, author
Cambridge University Press, 1941
Buku Teks