https://www.epsu.org/sites/default/files/article/files/EPSU%20Report%20Outsourcing%20state_EN.pdf
https://www.brookings.edu/blog/up-front/2020/08/26/how-is-the-u-s-postal-service-governed-and-funded/?utm_campaign=Brookings%20Brief&utm_medium=email&utm_content=94132499&utm_source=hs_email
https://ec.europa.eu/epsc/sites/epsc/files/epsc_brief_passerelles_2.pdf?utm_source=POLITICO.EU&utm_campaign=042aa4f2be-EMAIL_CAMPAIGN_2019_01_16_02_43&utm_medium=email&utm_term=0_10959edeb5-042aa4f2be-190380769