<ref name="Wilson_&_Brown_1953">{{cite journal |first1=E. O. |last1=Wilson |first2=W. L., Jr. |last2=Brown |year=1953 |title=The subspecies concept and its taxonomic application |url=https://antcat.org/documents/3716/3503.pdf |journal=Systematic Zoology |publisher= |volume=2 |issue= |pages=97–111 |doi= }}</ref>