Steffen, Dirk «The Holtzendorff Memorandum of 22 December 1916 and Germany's Declaration of Unrestricted U-boat Warfare». The Journal of Military History, 68, 1, 2004, pàg. 215-224. DOI: 10.1353/jmh.2003.0412. ISSN: 0899-3718.
google.cat
books.google.cat
Smith, Leonard V.; Stephane, Audoin-Rouzeau; Becker, Annette. France and the Great War (en anglès). Cambridge University Press, 2003, p. 157. ISBN 0521666317.
Stephen Pope, Elizabeth-Anne Wheal, Keith Robbins, Brendan Eddison. «Kerenski Offensive». A: Keith Robbins. Dictionary of the First World War (en anglès). Pen & Sword Military Classics, 2003, p. 267. ISBN 9780850529791.
worldcat.org
Steffen, Dirk «The Holtzendorff Memorandum of 22 December 1916 and Germany's Declaration of Unrestricted U-boat Warfare». The Journal of Military History, 68, 1, 2004, pàg. 215-224. DOI: 10.1353/jmh.2003.0412. ISSN: 0899-3718.