Lot 42036 – 1930-38, one frame exhibit dedicated to the postage due issues of Bolivian philately

1930-38, postage dues, one frame exhibit dedicated to the “Multa” triangular issues (the only postage dues issued in Bolivian philately), written up on pages including the only known Perkins Bacon archival material (10): die progressive and final proofs, complete sheets and multiples, specimens issued for UPU countries, postal history items with two of only five covers recorded in the first issue, and non-philatelic usages in the second issue, a very interesting and unique collection enriched by a good research, viewing suggested.