The Ministerial post office on Corfou. Usage of 45c. stamp. Double weight registered cover fr. with 2x10c+45c. French stamps (double weight foreign registered letter rate) canc. with linear "POSTES SERBES" and posted from "MINISTARSKA*23.7.-917" with Serbian censorship "CENSURE/MILITAIRE SERBE" in red , arr. "GENEVE*18.VIII.17". The 45c. stamp was not sold at the Ministarska office, but it was available in the Salonica front. UNIQUE. RR.