Handelman, Howard, author
Pearson/Prentice Hall, 2006
Buku Teks
Dixon, Chris J., author
Routledge, 2015
Buku Teks
Mathur, Hari Mohan, author
Sage, 1986
Buku Teks
Todaro, Michael P., author
Longman, 1992
Buku Teks
World Bank
Oxford University Press, 1991
Buku Teks