7Porter M E. Competitive Strategy: Techniques for Analyzing Indus- try and Competitors [ M]. Free Press, 1980.
8Robinson R B, Pearce J A. Planned Patterns of Strategic Behavior and Their Relationship to Business -unit Performance[ J]. Strategic Management Journal, 1988, 9 (1) : 43 - 60.
9Thomhill S, White R E. Strategic Purity: A Multi - industry Eval- uation of Pure vs. Hybrid Business Strategies [ J ]. Strategic Man- agement Journal, 2007, 28(5) : 553 - 561.
10Hall W K. Survival Strategies in a Hostile Environment[ J]. Harvard Business Review, 1980, 58(5) : 75 - 87.