Der Handelskrieg mit U-Booten

by - Spindler; Arno
(The Trade Warfare with U-boats)
1932, Mittler & Sohn Verlag
These books cover only operations against enemy trade ships. For operations against warships, see Gayer, Albert. These books are the most important source for this topic. Very well researched, covering every patrol and including a lot of data.
These books were very rare. At present you have to pay for volume 4 & 5 some 500 DM in Germany, but the problem is not mainly the money, the problem is to get a copy!

Volume I : Vorgeschichte (Prehistory) 1932
Volume II : Februar bis September 1915 (February to September 1915) 1933
Volume III : Oktober 1915 bis Januar 1917 (October 1915 to January 1917) 1934
Volume IV : Februar bis Dezember 1917 (February to December 1917) 1941/1966
Volume V : Januar bis November 1918 (January to November 1918) 1966

La guerra al commercio con i sommergibili

by - Spindler, Arno
(The submarine war on commerce)
1934, Roma
8 maps
These books cover only operations against enemy trade ships. For operations against warships, see Gayer, Albert. These books are the most important source for this topic. Very well researched, covering every patrol and including a lot of data.

La guerre sous-marine

by - Spindler, Arno
(The underwater war)
1935, Payot, Paris
3 volumes
These books cover only operations against enemy trade ships. For operations against warships, see Gayer, Albert. These books are the most important source for this topic. Very well researched, covering every patrol and including a lot of data.