Keefe, William J.
The American legislative process congress and the state
Prentice-Hall, 1994
 Buku Teks
American government
by Susan Welch ... [and others]
Thomson, 2006
 Buku Teks
Sayre, Wallace S.
American government
Barnes & Noble, 1964
 Buku Teks
Posey, Rollin Bennett
American government
Littlefield, Adam, 1958
 Buku Teks
Vance, Stanley C.
American industries
Prentice-Hall, 1955
 Buku Teks