^ abWilliams, David, Wartime Disasters at Sea, Patrick Stephens Limited, Nr Yeovil, UK, 1997, p.225 (figure of 494 merchant vessels); Brustat-Naval, Fritz, Unternehmen Rettung, Koehlers Verlagsgeschellshaft, Herford, Germany, 1985, p.240 (figure of 790 vessels of all types); Koburger, Charles W., Steel Ships, Iron Crosses, and Refugees, Praeger Publishers, NY, 1989, p.92 (figure of 1,080 merchant vessels).
^Prince, Cathryn J. (2014). Death in the Baltic: The World War II Sinking of the Wilhelm Gustloff. St.Martin's Griffin. ISBN978-1137279194