Russett, Bruce
Wadsworth, 2010
Buku Teks
Kinsella, David
Wadsworth, Cengage Learning, 2013
Buku Teks SO
resources for the future, 1981
Buku Teks
edited by Mathew J. Betz, Pat McGowan and Rolf T. Wigand
Duke Press Policy Studies, 1984
Buku Teks
Christensen, Kit R.
McGraw-Hill, 2002
Buku Teks