Ndolu, Freddy
IndonesiaSatu Publisher, 2009
Buku Teks
Ndolu, Freddy
IndonesiaSatu Publisher, 2009
Buku Teks
K.H. Abdurahman Wahid
Kompas, 2007
Buku Teks
Easton, David
Prentice-Hall, 1965
Buku Teks
Akbar Tandjung Institute, 2005
Majalah, Jurnal, Buletin