Bulgaria 1917 WW1 printed "Prisoner of War Correspondence" stampless (post-free) cover (text in Russian & French). From British POW held at camp in Philippopolis, Bulgaria, to Ireland. Large red Bulgarian military h/s (partly unclear), Sofia d/s 14.XI.17 & red London F.S. machine d/s JAN 14 18 (long transit!). Large "Opened by Censor PW 170" label on back. Vert central fold & 2cm edge tear. Unusual item