Rosen, George
Free of Glencoe, 1962
Buku Teks
Hasan, K.S.
MacDonald and Evans, 1979
Buku Teks
Gupta, G.P.
Publishing House , 1959
Buku Teks
Fisher, Douglas
Richard D. Irwin , 1980
Buku Teks
selected by a committee of the American Economic Association
George Allen and Unwin, 1955
Buku Teks