Bateman, I. J., & Willis, K. G. (1999). Valuing environmental preferences: Theory and practice of the contingent valuation method in the US, EU, and developing countries. Oxford University Press.

Bateman, Ian J., and Kenneth George Willis. Valuing Environmental Preferences: Theory and Practice of the Contingent Valuation Method in the US, EU, and Developing Countries. Oxford: Oxford University Press, 1999.

Bateman, Ian J., and Kenneth George Willis. Valuing Environmental Preferences: Theory and Practice of the Contingent Valuation Method in the US, EU, and Developing Countries. Oxford University Press, 1999.