{{sfn | McKenna | Bell | Bell | Bell | 1997 | p=}}
* {{cite book | last=McKenna | first=Malcolm C. | last2=Bell | first2=Susan | last3=Bell | first3=Professor Susan K | last4=Bell | first4=Susan K. | last5=Simpson | first5=George Gaylord | last6=Simpson | first6=Professor George Gaylord | title=Classification of Mammals Above the Species Level | publisher=Columbia University Press | publication-place=New York | date=1997 | isbn=0-231-11012-X}}
<ref name="e900">{{cite book | last=McKenna | first=Malcolm C. | last2=Bell | first2=Susan | last3=Bell | first3=Professor Susan K | last4=Bell | first4=Susan K. | last5=Simpson | first5=George Gaylord | last6=Simpson | first6=Professor George Gaylord | title=Classification of Mammals Above the Species Level | publisher=Columbia University Press | publication-place=New York | date=1997 | isbn=0-231-11012-X | page=}}</ref>