* {{cite book | last=Kenny | first=Anthony John Patrick | title=Wittgenstein | publisher=Suhrkamp | publication-place=Frankfurt am Main | date=1989 | isbn=3-518-27669-7 | language=de}}
<ref name="b322">{{cite book | last=Kenny | first=Anthony John Patrick | title=Wittgenstein | publisher=Suhrkamp | publication-place=Frankfurt am Main | date=1989 | isbn=3-518-27669-7 | language=de | page=}}</ref>