cover 1c-10c Kans.-Nebr. overprints (658-679), complete sets, tied by 'Washington, D.C. May 1, 1929' First Day machine slogan cancels on separate matched covers with typewritten address, 1c and 1½c in horizontal pairs, all have faint negligible toning marks in the extreme corners from prior corner mounts, otherwise fine-very fine sets, Scott retail $1,377.50