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.