<ref name="Hall_&_Smith_1951">{{cite journal |first1=D. W. |last1=Hall |first2=I. C. |last2=Smith |year=1951 |title=Studies in Pharaoh's ant, ''Monomorium'' ''pharaonis'' (L.). (6) External characters, size variation and cephalic ratios |url=https://antcat.org/documents/1628/12090.pdf |journal=Entomologist's Monthly Magazine |publisher= |volume=87 |issue= |pages=217–221 |doi= }}</ref>