Ungerer, Horst
International Monetary Fund , 1983
Buku Teks
Woodworth, George Walter, author
McGraw-Hill, 1950
Buku Teks
Lee, Sheng-Yi, author
Singapore University Press, 1974
Buku Teks
Butlin, S.J.
Melbourne University Press, 1953
Buku Teks
Simpson, Thomas D., author
Prentice-Hall, 1987
Buku Teks