<ref name="Robbins_1910">{{cite journal |first1=W. W. |last1=Robbins |year=1910 |title=An introduction to the study of the ants of northern Colorado |url=http://hymfiles.biosci.ohio-state.edu/pdfs-osuc/22805/22805.pdf |journal=University of Colorado Studies |publisher= |volume=7 |issue= |pages=215–222 |doi= }}</ref>