Gaya APA
NIBBERING, J. (1986).
Socio-economic conditions and developments Kali Konto Upperwatershed .
Malang:
Proyek Kali Konto.
Gaya MLA
NIBBERING, J.W..
"Socio-economic conditions and developments Kali Konto Upperwatershed".
Malang:
Proyek Kali Konto,
1986.
Buku.