<ref name="Heil_et_al_2009">{{cite journal |first1=M. |last1=Heil |first2=M. |last2=Gonzalez-Teuber |first3=L. W. |last3=Clement |first4=S. |last4=Kautz |first5=M. |last5=Verhaagh |first6=J. S. |last6=Bueno |year=2009 |title=Divergent investment strategies of ''Acacia'' myrmecophytes and the coexistence of mutualists and exploiters |url=https://antcat.org/documents/4426/Heil_et_al_2009_PNAS.pdf |journal=Proceedings of the National Academy of Sciences of the United States of America |publisher= |volume=106 |issue= |pages=18091–18096 |doi= }}</ref>