1929

Felix with his sons, Eberhard (7) (my father) and Willibald (9)

1928

First Flight Air Mail Graf Zeppelin
Top addressed to Willibald Knoll - Bottom addressed to Eberhard Knoll
The handwritten notation asks that it be re-addressed if undeliverable. Note the date and note the date on the following photo

Willibald, Anne Knoll and Eberhard bound for United States October 1928
aboard the Steamship MS Bremen

1940

Felix - Willibald - Eberhard - 1940