Hailey
Macmillan, 1950
Buku Teks
Buss, Claude Albert, author
D. Van Nostrand Company, 1958
Buku Teks
Michael, Franz, author
Henry Holt and Co., 1956
Buku Teks
The University of Chicago Press, 1950
Buku Teks
Dobbin, Christine, author
Curzon, 1996
Buku Teks