Hicks, John R., author
Clarendon Press, 1957
Buku Teks
Harrod, R.F., author
Macmillan, 1956
Buku Teks
Constant, F. Woodbridge (Frank Woodbridge), 1904-, author
Addison-Wesley, 1967
Buku Teks
Harris, Myra A., author
Prentice-Hall, 1997
Buku Teks
Larson, Kermit D., author
Irwin, 1988
Buku Teks