cover 50pa. green (2, perf. 9½x12) one showing plate flaw "56" in upper right corner, affixed to 1879 (22 Dec.) envelope registered to Hungary and tied by "OBRENOVACKE" c.d.s., framed "PREPORUCENO" h.s. adjacent, reverse showing two types of Belgrade c.d.s.; some soiling, though scarce. M.18IC. Photo