Van Waelbroeck, J. “Les Applications De l’économétrie à La Gestion Des Affaires Publiques”. JORBEL - Belgian Journal of Operations Research, Statistics, and Computer Science, vol. 6, no. 3-4, Jan. 1966, pp. 50-54, https://www.orbel.be/jorbel/index.php/jorbel/article/view/56.