Hovey, Craig, author
Prenada, 2009
Buku Teks
Soros, George, author
Yayasan Obor Indonesia, 2007
Buku Teks
Lamont, Douglas, author
Blackwell Publishers, 1996
Buku Referensi
Wisnu Arya Wardhana, author
Andi, 2010
Buku Teks
Gabungan Pengusaha Kelapa Sawit Indonesia, 2013
Buku Teks