AIRSHIP ERA 1897-1936, a fantastic collection of countless documents, newspaper articles, illustrations, photographs, and engravings by Woelfert, covering registered mail 34 and registered mail 100 up to the Zeppelin airships, including a cover "Bordbuch der Sachsen 9. Mai 1914 - 31. Juli 1914" handwritten "G. Hacker", a true treasure trove not only for specialists.