6 Groschen to 1 zloty Hitler with vertical overprint "POCZTA POLOWA / 1. VIII. 1944 / WARSZAWA", complete set of ten values, some with margin of sheet, perfectly mint never hinged, expertized Krawczyk and Petriuk BPP, photo expertize Petriuk BPP (1988) "only a few sets have survived. all mint never hinged and in outstanding quality. ", Michel 3000.-, scarce and sought issue