Flores Velásquez, P., Martínez de Anguita, P., Romero Calcerrada, R., Novillo, C.J. and Ruiz, M.A. 2008. Payment for environmental services between the adding and the subsidization: application to the valuation of the landscape in the San Juan dam, Madrid, Spain. Forest Systems. 17, 1 (Jul. 2008), 39-53. DOI:https://doi.org/10.5424/srf/2008171-01022.