Stanfield, Peggy S. , author
Jones & Bartlett Learning, 2012
Buku Teks
Farley, John E., author
Prentice-Hall, 1987
Buku Teks
Allyn and Bacon, 1993
Buku Teks
Farley, O. William, 1934-, author
Pearson Education, 2012
Buku Teks
Lowi, Theodore J.
Macmillan, 1976
Buku Teks