1. Adamowicz, W. L., J. Louviere, and M. Williams. 1994. Combining Revealed and Stated Preference Methods for Valuing Environmental Amenities. Journal of Environmental Economics and Management 26:271–292
2. Cameron, T. A. 1992. Combining Contingent Valuation and Travel Cost Data for the Valuation of Nonmarket Goods. Land Economics 68:302–317.
3. Carmines, E. G., and R. A. Zeller. 1979. Reliability and Validity Assessment. Beverly Hills, CA: Sage Publications.
4. Chu, A., D. Eisenhower, M. Hay, D. Morganstein, J. Neter and J. Waksberg. 1992. Measuring Recall Error in Self-Reported Fishing and Hunting Activities. Journal of Official Statistics 5:13–39.
5. Freeman, A. M. III. 1993. The Measurement of Environmental and Resource Values:Theory and Methods. Washington, DC: Resources for the Future.