^Helgason, Guðmundur. Most Successful U-boats. German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. [2022-03-17]. (原始内容存档于2019-09-15).
^ 9.09.1Helgason, Guðmundur. Ships hit by UB 57. German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. [2014-12-05].
^Helgason, Guðmundur. Ships hit during WWI: Moldavia. German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. [2022-04-27].
^Helgason, Guðmundur. Ships hit during WWI: Westmoreland. German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. [2022-04-27].
参考资料
Gröner, Erich; Jung, Dieter; Maass, Martin. U-boats and Mine Warfare Vessels. German Warships 1815–1945 2. 由Thomas, Keith; Magowan, Rachel翻译 (London: Conway Maritime Press). 1991. ISBN 0-85177-593-4.
Rössler, Eberhard. Geschichte des deutschen U-Bootbaus. 1: Entwicklung, Bau und Eigenschaften der deutschen U-Boote von den Anfängen bis 1943. Band 1. Augsburg: Bechtermünz. 1996. ISBN 3-86047-153-8.