Bardes, Barbara A., author
Thomson/Wadsworth, 2006
Buku Teks
Asher, Herbert B., author
The Dorsey Press, 1980
Buku Teks
Harris, Myra A., author
Prentice-Hall, 1997
Buku Teks
Myers, John G., author
Prentice-Hall, 1980
Buku Teks
Bander, Edward J., author
Balinger, 1978
Buku Teks