Dolbeare, Kenneth M., author
D.C. Heath, 1985
Buku Teks
by William J. Keefe ... [and others]
The Dorsey Press, 1983
Buku Teks
Brewster, Lawrence G., author
St. Martin`s Press, 1982
Buku Teks
Brewster, Lawrence G., author
Thomson wadsworth, 2004
Buku Teks
Clowers, Myles L., author
McGraw-Hill, 1973
Buku Teks