Dillard, Dudley D., author
Prentice-Hall, 1949
Buku Teks
Robertson, D.H., author
Staples Press, 1948
Buku Teks
Davidson, Paul, author
Edward Elgar, 2011
Buku Teks
Torr, Christopher, author
Westview Press, 1988
Buku Teks
Pigou, A.C. (Arthur Cecil), 1877-1959, author
Macmillan, 1956
Buku Teks