Military post offices on the Salonica front. Registered cover (registry label) fr. with 3x5c+10c+25c. (foreign registered letter rate) and posted from "TRESOR ET POSTES*504*17 4 17" with Serbian censorship canc. "PREGLEDALA/VOJNA CENZURA (39)", via "POSTA MILITARE*35a DIVISIONE*18.4.17" and "POSTA MILITARE*24.4.17", arr. "MILANO25.4.17".