<ref name="Bourke_&_Franks_1991">{{cite journal |first1=A. F. G. |last1=Bourke |first2=N. R. |last2=Franks |year=1991 |title=Alternative adaptations, sympatric speciation and the evolution of parasitic, inquiline ants |url= |journal=Biological Journal of the Linnean Society |publisher= |volume=43 |issue= |pages=157–178 |doi= }}</ref>