European national groups. Westport, Conn: Greenwood Press. hlm. 264. ISBN 9780313309847. Haywood 1999, Dark Age Naval Power. Haywood uses the term 'North German'...
Dictionary of European National Groups. Greenwood Publishing Group. ISBN 9780313309847. LCCN 99046040. Müller, Rudolf-Dieter (2012). The Unknown Eastern Front:...