Source: https://www.devoirat.net/app/download/10910996652/Cours+-+%C3%89conomie+-+Section+1+la+croissance+%C3%A9conomique+et+sa+mesure+-+Bac+Economie+%26+Gestion+%282019-2020%29+Mme+Hanen+Welhazi.pdf