Lot 40118 – 1929 Bunavad airmail cover to Prague franked by all 4 values incl 1l on 5l in horiz. gutter pair

1929 Airmail, all four values in pairs except for the 1L in strip of three, tied by Sofia cds’s to airmail cover to Prague, including 1L on 5L in horizontal gutter pair, with arrival alongside, one 4L stamp toned at upper left; against the terms of the contract between Bunavad and the Bulgarian PTT, the whole postage is paid by Bunavad airmails incl. two values which were not valid anymore, and the cover was mailed without reclamations to Prague. Very interesting and scarce.