* {{cite book | last=Sheppard | first=Lucy J. | last2=Cape | first2=J. Neil | title=Forest Growth Responses to the Pollution Climate of the 21st Century | publisher=Springer Science & Business Media | date=2013-03-09 | isbn=978-94-017-1578-2}}
<ref name="c061">{{cite book | last=Sheppard | first=Lucy J. | last2=Cape | first2=J. Neil | title=Forest Growth Responses to the Pollution Climate of the 21st Century | publisher=Springer Science & Business Media | date=2013-03-09 | isbn=978-94-017-1578-2 | page=}}</ref>