Williams, Phil, author
Thomson Wadsworth, 2006
Buku Teks
Shimko, Keith L., 1962-, author
Cengage Learning, 2016
Buku Teks
Papp, Daniel S., author
Macmillan, 1984
Buku Teks
Papp, Daniel S., author
Allyn and Bacon, 1997
Buku Teks
Papp, Daniel S., author
Macmillan, 1988
Buku Teks