Postal development report 2022 [documento eletrónico] : postal journey towards a sustainable future / Universal Postal Union
Statistique des services postaux 2021 [documento eletrónico] / Union Postale Universelle
State of the postal sector 2023 [documento eletrónico] : a hyper-collaborative path to postal development / Universal Postal Union
Statistique des services postaux 2022 [documento eletrónico] / Union Postale Universelle