Griffith, Ernest S.
New York University press, 1956
Buku Teks
Matthews, Donald R.
The University of North Carolina Press, 1960
Buku Teks
Howard D.Samuel
Henry Holt and Company, 1953
Buku Teks
Griffith, Ernest S.
New York University press, 1952
Buku Teks
Editor by Lawrence C.Dood; Bruce I. Oppenheimer
Congressional Quarterly Press, 1981
Buku Teks