Geiger, Theodore, author
National Planning Association , 1963
Buku Teks
edited by Richard M. Bird and Milka Casanegra de Jantscher
International Monetary Fund, 1992
Buku Teks
Greenberg, Simon, author
Cambridge University Press, 2011
Buku Teks
Carroll, Thomas F.
Connecticut Kumarian Press , 1992
Buku Teks
Korten, Frances F., author
The Pathfinder Fund, 1977
Buku Teks