McLeod, Raymond, author
Macmillan, 1990
Buku Teks
McLeod, Raymond, author
Prentice-Hall, 1995
Buku Teks
McLeod, Raymond, author
Macmillan, 1993
Buku Teks
McLeod, Raymond, author
Prentice-Hall, 1995
Buku Teks
Kroeber, Donald W.
Macmillan Publishing Company, 1990
Buku Teks