 The book has been published in 1979 by the Institut für Zeitgeschichte in Munich  Later he took part in projects of the Institut für Zeitgeschichte, Munich, and Institute for Research of Antisemitism, director Wolfgang Benz, Berlin, about the Holocaust, especially the fate of Bulgarian Jews and the Jews in Bulgarian occupied territories (Macedonia and Northern Greece).From 1976 to 2010 he was head of the Department for German language and East European languages at Volkshochschule Köln - the second largest adult high school in Germany.He has been also for many years a lecturer in the Institute of East European History at Universität Köln.