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
Williams, Phil, author
Thomson Wadsworth, 2006
Buku Teks
Chan Stephen; Moore Cerwyn
Sage, 2006
Buku Teks