SÁENZ LOZANO, J. L.; BRAÑAS GARZA, P. Cities size systems: A product differentiation model. Estudios Económicos de El Colegio de México, [S. l.], v. 16, n. 1, p. 73–104, 2001. DOI: 10.24201/ee.v16i1.209. Disponível em: https://estudioseconomicos.colmex.mx/index.php/economicos/article/view/209. Acesso em: 17 jul. 2024.