Madeira Nogueira, J. and Asano de Medeiros, M.A. 1999. VALUING THINGS THAT DO NOT HAVE VALUE. EXISTENCE VALUE, ECONOMICS AND ENVIRONMENT. Science & Technology Journals. 16, 3 (Jan. 1999), 59–83. DOI:https://doi.org/10.35977/0104-1096.cct1999.v16.8905.