APA (7e ed.) Bronvermelding

PORTER MICHAEL E. (1980). COMPETITIVE STRATEGY. FREE PRESS.

Chicago (17e ed.) Bronvermelding

PORTER MICHAEL E. COMPETITIVE STRATEGY. NEW YORK: FREE PRESS, 1980.

MLA (9e ed.) Bronvermelding

PORTER MICHAEL E. COMPETITIVE STRATEGY. FREE PRESS, 1980.