Military Post Offices. Degree of Rarity. Registered cover posted from "VOJNA POSTA*Br.96*2.11.17" (M.R.Vukovic study page 177, rarity R) with Serbian censorship "PREGLEDALA/VOJNA CENZURA (56)" fr. with 2x25c. cancelled with "TRESOR ET POSTES*504*16 11 17", arr. "WEESEN*6.XII.17".