（1）Hammitt, W. E., Backlund, E. A., & Bixler, R. D. (2004).
Experience use history, place bonding and resource substitution of trout anglers during recreation engagements.  
（2）Hendee, J. C., & Burdge, R. J. (1974).
The substitutability concept: Implications for recreation research and management.
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