Palmby, Clarence D.
The Interstate Printers, 1985
Buku Teks
Randall, Clarence B.
The University of Chicago Press, 1954
Buku Teks
Grampp, William D.
Richard D. Irwin , 1953
Buku Teks
The University Of Michigan Press, 1999
Buku Teks
The University of Michigan Press, 1999
Buku Teks