Columbia subject headings:
Harvard subject headings:
Ivens, Heinrich Magnus, 1878-1966--Correspondence.
Soldiers--Germany--Correspondence
World War, 1914-1918--Personal narratives, German
Princeton subject headings:
Ivens, Heinrich Magnus, 1878-1966--Correspondence.
Soldiers--Germany--Correspondence.
World War, 1914-1918--Personal narratives, German.