<ref name="Ross_&_Carpenter_1991">{{cite journal |first1=K. G. |last1=Ross |first2=J. M. |last2=Carpenter |year=1991 |title=Phylogenetic analysis and the evolution of queen number in eusocial Hymenoptera |url= |journal=Journal of Evolutionary Biology |publisher= |volume=4 |issue= |pages=117–130 |doi= }}</ref>