Hallo Mark,

On the Black Sea there are also:
"Letzter Befehl versenken" by Rudolf Arendt, ISBN 3-8132-0543-6;
"Deutsche U-Boote zum Schwarzen Meer" by Gerd Enders, ISBN 3-8132-0520-7.

For books which cover at least partly the Monsun-boats, there are:
"U-Boat far from home" by David Stevens, ISBN 978-1-86448-267-6;
"Hitler's grey wolves: U-Boats in the Indian Ocean" by Lawrence Paterson, ISBN 978-1-85367-615-4;
"War in the southern oceans" by Turner, Gordon-Cumming and Betzler (no ISBN, Oxford University Press, 1961);
"Wings of the dawning" by Arthur Banks, ISBN 978-1-90139-400-9.

Regards,
Walter
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