1. Estimating option price and existence values for wildlife resources;Brookshire;Land Economics,1983
2. The economic benefits of surface water quality improvements in developing countries: a case study of Davao;Choe;Philippines. Land Economics,1996
3. Capital returns from soil conservation practices;Ciriacy-Wantrup;Journal of Farm Economics,1947
4. Cummings R.G, Brookshire D.S., Schulze W.D., (1986), Valuing environmental goods: a state of the arts assessment of the contingent valuation method. Totowa, NJ: Roweman and Allanheld.