Anderson, Christopher
Simon & Schuter , 1994
Buku Teks
Kendall/Hunt, 1982
Buku Teks
Millspaugh, Arthur Chester, 1883-1955
The Brookings Institution, 1942
Buku Teks
Millspaugh, Arthur Chester, |1883-1955
The Brookings Institution, 1942
Buku Teks
Quadrangle Books, 1969
Buku Teks