Sources
Fritz Lang's passport: Deutsche Kinemathek, Berlin. Berlin in March 1933: Gerd Albrecht, Nationalsozialistische Filmpolitik (1969), pp. 12–13.
Goebbels' speech in Kaiserhof, 28 March 1933: given in extenso in Albrecht, pp. 439 ff.
Lang's part in NSBO: Cinegraph, Lexikon zum deutschsprachigen Film (1984), p. D3, also Cahiers du Cinéma , no. 99, September 1959, p.29.
Interview with Lang giving his version of the story: Movie no. 4, November 1962, pp. 4–5.
For statements made by Lang: Francis Cortade, Fritz Lang (1963), p. 21. See also P. M. Jensen, The Cinema of Fritz Lang (1969), p. 104; Lotte Eisner, Fritz Lang (1976), p. 131; Ludwig Maibohm, Fritz Lang (1981), pp. 164–169; N. Simsolo, Fritz Lang (1982), p. 46; M. Töteberg, ed., Fritz Lang in Selbstzeugnisse (1985), p. 78, p. 136.
For embellishments: Lotte Eisner, in Ich hatte einst ein schönes Vaterland (1984), relates how Lang was wont to tell with great delight about his conversation with Goebbels and how "each time he embellished it a little more." (pp. 127–28)