* {{cite book | last=Logan | first=Francis Donald | title=Die Wikinger in der Geschichte | publisher=Philipp Reclam jun | publication-place=Stuttgart | date=1987 | isbn=3-15-010342-8 | language=de}}
<ref name="i891">{{cite book | last=Logan | first=Francis Donald | title=Die Wikinger in der Geschichte | publisher=Philipp Reclam jun | publication-place=Stuttgart | date=1987 | isbn=3-15-010342-8 | language=de | page=}}</ref>