Accounting for Negative, Zero and Positive Willingness to Pay for Landscape Change in a National ParkNick Hanley, Sergio Colombo, Bengt Kriström, Fiona Watson†
Journal of Agricultural EconomicsVolume 60, Issue 1, pages 1–16, February 2009



http://onlinelibrary.wiley.com/doi/10.1111/j.1477-9552.2008.00180.x/abstract