Hagopain, Mark N.
Longman, 1978
Buku Teks
Facts on File Publications, 1986
Buku Teks
Rose, Richard, 1933-, author
Routledge, 2005
Buku Teks
Inter-Parliamentary Union
Facts on File Publications, 1986
Buku Referensi
Inter-Parliamentary Union
Facts on File Publications, 1986
Buku Referensi