Columbia subject headings:
Germany. Heer--Military life--History--20th century.
Hamburg (Germany)--History, Military--20th century.
Hamburger Turnerschaft von 1816.
Middle class--Germany--History--20th century.
Military service, Voluntary--Germany--History--20th century.
Soldiers--Germany--Hamburg--Correspondence.
World War, 1914-1918--Germany--Hamburg.
World War, 1914-1918--Social aspects--Germany.
Harvard subject headings:
Germany--Armed Forces--Civilian employees--History--20th century.
Germany--Armed Forces--Postal service--History--20th century.
Gymnastics--Germany--Hamburg--History--20th century.
Soldiers--Germany--Hamburg--Correspondence.
World War, 1914-1918--Personal narratives, German
World War, 1914-1918--Postal service--History.
Princeton subject headings:
Germany--Armed Forces--Civilian employees--History--20th century.
Germany--Armed Forces--Postal service--History--20th century.
Gymnastics--Germany--Hamburg--History--20th century.
Soldiers--Germany--Hamburg--Correspondence.
World War, 1914-1918--Personal narratives, German.
World War, 1914-1918--Postal service--History.