World Jewish Population Study 2010, by Sergio DellaPergola, ed. Dashefsky, Arnold, Sheskin, Ira M., published by Association for the Social Scientific Study of Jewry (ASSJ), North American Jewish Data Bank, The Jewish Federations of North America, November 2010
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Erich S. Gruen, Diaspora: Jews Amidst Greeks and RomansHarvard University Press, 2009 pp. 3–4, 233–34: 'Compulsory dislocation, .…cannot have accounted for more than a fraction of the diaspora. … The vast bulk of Jews who dwelled abroad in the Second Temple Period did so voluntarily.' (2)' .Diaspora did not await the fall of Jerusalem to Roman power and destructiveness. The scattering of Jews had begun long before-occasionally through forced expulsion, much more frequently through voluntary migration.'
