Noto: Esperanto estis siatempe (1923) agnoskita fare de Universala Poŝta Unio kiel lingvo por Telegram- komunikado ⇒ "The Universal Postal Union decided that Esperanto will no longer be considered as a code but clearly as a language: but the payment will longer be charged by character, but by word". Fonto: Official acknowledgments related to Esperanto.
upu.int
(en) Anna Tibaijuka, Antaŭparolo, Addressing the world – An address for everyone. White paper, p. 6, Universala Poŝta Unio, 2009
