Shapiro, Martin
The Free Press, 1968
Buku Teks
Cooper, Phillip J., author
Oxford University Press , 1988
Buku Teks
Leiserson, Avery
The University of Chicago Press, 1942
Buku Teks
Robinson, Glen O., author
West Publishing, 1986
Buku Teks
Robinson, Glen O., author
West Publishing, 1974
Buku Teks