Artikel Jurnal
Dobelstein, Andrew W., author
Wadsworth, 2003
Buku Teks
Pigou, A.C. (Arthur Cecil), 1877-1959, author
Macmillan, 1950
Buku Teks
Baumol, William J., author
Mass. Harvard University Press, 1952
Buku Teks
Friedlander, Walter A., author
Prentice Hall of India, 1982
Buku Teks