Lehman, D. R. and Weiner, R. S., Analysis for Marketing Planning, 2nd edn, Irwin,
Homewood, Illinois, 1991.
Porter, M. E., Competitive Strategy, Free Press, New York, 1980, p. 4.
■ Further reading
Aaker, D., Strategic Market Management, 4th edn, Chapters 4–7, Wiley, New York,
1995.
Davidson, H., Even More Offensive Marketing, Chapter 5, Penguin Books, London,
1997.
Mudie, P., Marketing: An Analytical Perspective, Chapter 2, Prentice Hall, Hemel
Hempstead, 1997.
External analysis 35