Columbia subject headings:
Harvard subject headings:
Marine engineers--Germany--Diaries.
Shipwrecks--North Sea.
Submarines (Ships)--Germany
Trinks, Georg--Diaries.
UC 71 (Submarine)
UC 71 (Submarine)--History--Sources.
Underwater exploration--North Sea.
World War, 1914-1918--Naval operations--Submarine
Princeton subject headings:
Diaries.
Marine engineers--Germany--Diaries.
Shipwrecks--North Sea.
Submarines (Ships)--Germany.
Trinks, Georg--Diaries.
UC 71 (Submarine)
UC 71 (Submarine)--History--Sources.
Underwater exploration--North Sea.
World War, 1914-1918--Naval operations--Submarine.