Lampert of Hersfeld, Annales, a.1071, p. 132; Creber, Alison (2019-04-22). "Breaking Up Is Hard To Do: Dissolving Royal and Noble Marriages in Eleventh-Century Germany". German History. 37 (2): 149–171. doi:10.1093/gerhis/ghy108. ISSN0266-3554..
manfred-hiebl.de
K-H. Lange, Die Grafen von Northeim (950-1144). Politische Stellung, Genealogie und Herrschaftsbereich. Beiträge zur Geschichte des sächsischen Adels im Hochmittelalter (Dissertation, Kiel, 1958), pp. 142-145, accessible online at: Genealogie Mittelater
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Lampert of Hersfeld, Annales, a.1071, p. 132; Creber, Alison (2019-04-22). "Breaking Up Is Hard To Do: Dissolving Royal and Noble Marriages in Eleventh-Century Germany". German History. 37 (2): 149–171. doi:10.1093/gerhis/ghy108. ISSN0266-3554..