MacNamee, Brian
Routledge, 1995
Buku Teks
Lovelock, Christopher H., author
McGraww-Hill, 1993
Buku Teks
Berg, Thomas L., author
Anchor Books, 1971
Buku Teks
Rapp, Stan, author
McGraw-Hill , 1994
Buku Teks
Kotler, Philip, author
Pearson, 2014
Buku Teks