Higuera Ramírez, G. L.; Calatayud Mendoza, A. P. Conomic Valuation of the Recreational Environmental Service in the Valle de Piedras Encimadas, Puebla-Mexico. Sem. Econ. 2017, 6 (1), 7-25. https://doi.org/10.26867/se.2017.v06i1.59.