Lovelock, Christopher H.
McGraw-Hill, 1994
Buku Teks
Brown, Stanley A.
Prentice-Hall, 1992
Buku Teks
Porter, Michael E.
The Free Press , 1990
Buku Teks
Bendell, Tony
Elex Media Komputindo, 2000
Buku Teks
Bendell, Tony
Elex Media Komputindo, 2000
Buku Teks