1. Bockstael , N. M. Hanemann I. Strand Measuring the benefits of water quality improvements using recreation demand models Benefit Analysis Using Indirect or Imputed Market Methods II College Park 1985
2. The hedonic travel cost method;Brown;Rev. Econ. Stat.,1984
3. Bureau of Reclamation Report on refuge water supply investigations Central Valley Hydrologic Basin, California 1 Sacramento, Calif. 1987