Sources almost invariably report the submarine as U-boat 13 or U-13. UB-13 was the only extant U-boat numbered 13 in March 1916; U-13 and UC-13 had been lost in 1914 and 1915, respectively.See: Helgason, Guðmundur. "WWI U-boats: U 13". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 16 March 2009.
Helgason, Guðmundur. "WWI U-boats: UB 13". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 16 March 2009.
Helgason, Guðmundur. "WWI U-boats: UC 13". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 16 March 2009.
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Pickford 2006, p. 213. Pickford, Nigel (2006). Lost Treasure Ships of the Northern Seas: A Guide and Gazetteer to 2000 Years of Shipwreck. London: Chatham. ISBN978-1-86176-250-4. OCLC67375472.
Pickford 2006, p. 214. Pickford, Nigel (2006). Lost Treasure Ships of the Northern Seas: A Guide and Gazetteer to 2000 Years of Shipwreck. London: Chatham. ISBN978-1-86176-250-4. OCLC67375472.