Munhakdongne, 2009
Buku Teks
Lester R. Brown...[et all.]
W.W Norton, 1990/1995
Buku Teks
Bloomfield, Harold H., author
Thorsons , 1995
Buku Teks
Andrews, Ted, author
llewellyn Publication, 2006
Buku Teks
Middleton, Neil, author
Pluto Press, 1993
Buku Teks