Germany 1921, set of 11 values 10Pf. - 1M., Overprinted "Plébiscite 20 mars 1921." Michel 30 - 40 / €350; Scott No. 16-26. This set corresponds to the Plebiscite Post of the Inter-Allied Commission of Government and Plebiscite in Upper Silesia (Commission Interalliée de Gouvernement et de Plébiscite de Haute Silésie).
