Hamoudi, Hamid, Isabel M. Rodríguez Iglesias, and Marcos Sanz Martín-Bustamante. 2015. “The Equivalence of Convex and Concave Transport Cost in a Circular Spatial Model With and Without Zoning”. Estudios De Economía 42 (1):pp. 5-20. https://estudiosdeeconomia.uchile.cl/index.php/EDE/article/view/37255.