Philately's Contribution to Labor. Charity. Overprint is bronze. Industry. 'Workers of the world, unite!'.
Post of the Soviet Union (<a href="https://ru.wikipedia.org/wiki/%D0%A0%D0%B5%D0%B9%D0%BD%D0%B4%D0%BE%D1%80%D1%84,_%D0%93%D1%8E%D0%BD%D1%82%D0%B5%D1%80-%D0%A4%D1%80%D0%B8%D0%B4%D1%80%D0%B8%D1%85_%D0%93%D0%B5%D1%80%D0%BC%D0%B0%D0%BD%D0%BE%D0%B2%D0%B8%D1%87" class="extiw" title="ru:Рейндорф, Гюнтер-Фридрих Германович">Günther Reindorff</a>).
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