Martínez García, J. D., and A. Leal Holguín. “Arbitrariness of Contractor Selection Criteria in the Bidding Processes. The Proportionality Principle As Protection Against Arbitrariness”. International Law: Revista Colombiana De Derecho Internacional, vol. 9, no. 19, Oct. 2011, pp. 223-68, https://revistas.javeriana.edu.co/index.php/internationallaw/article/view/13739.