The book "Die Nemesis von Potsdam" has 47 pages of bibliography  archives, demographic studies, official publications of the U.S., Great Britain, France, Switzerland, Poland, etc. besides secondary literature.  These sources are tken into account in some 1000 footnotes in the book, and brought up to date in the 14th revised and enlarged edition, which you can borrow from any library.  As far as German statistics on the deaths that resulted from the evacuation/flight/expulsion of the Germans, the figure of 2 million deaths is considered to be on the low side of the spectrum. As you may know, the German Red Cross, "Statistisches Bundesamt", "Heimatortskarteien", "Gesamterhebung" and other professional, not amateur institutions carried out careful demographic studies, especially in connection with the search for missing persons.  This work was carried out over many years, and the results were always the same  between 2 and 3 million missing and dead.  The fact that Poland was a victim of aggression and war crimes by both Germany and the Soviet Union does not justify or legalize the crimes committed against East Prussian farmers, Silesian coal miners, factory workers and their families.  JvA