{{sfn|Walter|Winter|Hagen|Jacobs|2015|p=}} * {{cite | last=Walter | first=Klaus-Peter | last2=Winter | first2=Markus | last3=Hagen | first3=Till | last4=Jacobs | first4=Tom | last5=Doyle | first5=Arthur Conan | title=Der Fall der "My Fair Lady" | publication-place=Remscheid | date=2015 | isbn=978-3-943732-84-9 | language=cy}}

<ref name="t891">{{cite | last=Walter | first=Klaus-Peter | last2=Winter | first2=Markus | last3=Hagen | first3=Till | last4=Jacobs | first4=Tom | last5=Doyle | first5=Arthur Conan | title=Der Fall der "My Fair Lady" | publication-place=Remscheid | date=2015 | isbn=978-3-943732-84-9 | language=cy | page=}}</ref>