1. PorterM.E., Competitive Advantage: Creating and Sustaining Superior Performance, New York, NY: Free Press, 1985.
2. PorterM.E., Competitive Advantage: Creating and Sustaining Superior Performance, New York, NY: Free Press, 1985.
3. PorterM.E., Competitive Advantage: Creating and Sustaining Superior Performance, New York, NY: Free Press, 1985.,p. 2.
4. Causal Ambiguity, Barriers to Imitation, and Sustainable Competitive Advantage
5. Causal Ambiguity, Barriers to Imitation, and Sustainable Competitive Advantage