E. N. . Carvalho Sousa Val, A. Hernández Santoyo, D. . Ciro de Oliveira, and W. . Freire da Rocha Jr, “Economic valuation of ecosystem goods and services in the Serra da Capivara National Park: an approach based on the Travel Cost Method”, S&N, vol. 32, pp. 766–777, Nov. 2020.