Badan Penelitian dan Pengembangan Pertanian Deptan, 2006
Majalah, Jurnal, Buletin
ILO UNDP , 1998
Buku Teks
Soepomo Poedjosoedarmo
Australian National University, 1982
Buku Teks
Indonesian Institute of Sciences, [date of publication not identified]
Buku Teks
Power, Jonathan
Longman, 1971
Buku Teks