Gaya APA
PORTER, M, E., HERYANTO, A. (1985).
Competitive Advantage: Creating and Sustaning Superior Performance .
Free Press:
New York.
Gaya MLA
PORTER, Michael, E.., HERYANTO, Ariel.
"Competitive Advantage: Creating and Sustaning Superior Performance".
Free Press:
New York,
1985.
Buku Teks.