Shortened footnote and citation:
{{sfn | Sommer | Vasey | 2006 | p=}}
* {{cite book | last=Sommer | first=Volker | last2=Vasey | first2=Paul L. | title=Homosexual Behaviour in Animals | publisher=Cambridge University Press | publication-place=Cambridge ; New York | date=2006-07-27 | isbn=0-521-86446-1 | oclc=ocm71798078}}
Named reference:
<ref name="y189">{{cite book | last=Sommer | first=Volker | last2=Vasey | first2=Paul L. | title=Homosexual Behaviour in Animals | publisher=Cambridge University Press | publication-place=Cambridge ; New York | date=2006-07-27 | isbn=0-521-86446-1 | oclc=ocm71798078 | page=}}</ref>