{{sfn|Gregory|Johnston|Pratt|Watts|2009|p=}}

* {{cite book | last=Gregory | first=Derek | last2=Johnston | first2=Ron | last3=Pratt | first3=Geraldine | last4=Watts | first4=Michael | last5=Whatmore | first5=Sarah | title=The Dictionary of Human Geography | publisher=John Wiley & Sons | publication-place=Chichester | date=2009-06-22 | isbn=978-1-4051-3288-6}}

<ref name="o484">{{cite book | last=Gregory | first=Derek | last2=Johnston | first2=Ron | last3=Pratt | first3=Geraldine | last4=Watts | first4=Michael | last5=Whatmore | first5=Sarah | title=The Dictionary of Human Geography | publisher=John Wiley & Sons | publication-place=Chichester | date=2009-06-22 | isbn=978-1-4051-3288-6 | page=}}</ref>