Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

PORTER MICHAEL E. COMPETITIVE STRATEGY TECHNIQUES. LONDON: FREE PRESS, 1980.

Cita MLA (9a ed.)

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