Shortened footnote and citation:
{{sfn | Zulehner | 1979 | p=}}
* {{cite book | last=Zulehner | first=Paul Michael | title=Umkehr, Prinzip und Verwirklichung | publisher=Knecht | publication-place=Frankfurt/M | date=1979-01-01 | isbn=3-7820-0418-3 | language=de}}
Named reference:
<ref name="u837">{{cite book | last=Zulehner | first=Paul Michael | title=Umkehr, Prinzip und Verwirklichung | publisher=Knecht | publication-place=Frankfurt/M | date=1979-01-01 | isbn=3-7820-0418-3 | language=de | page=}}</ref>