1931 Zeppelin Pollar Flight: Registered cover fr. with 35kop+2R USSR airmails imperforate (Mi 403B+405B) canc. "BRISE-GLACE MALYGUIN ARCTIQUE*18.VII.31", arr. "FRIEDRICHSHAFFEN*31.7.31". Cachet "Mit Eisbrecher Malygin und Luftschiff Gr Zeppelin/ARCHANGELSK-NORDPOL-FRIEDRICHSHAFFEN".