A Review of the Lower Miocene Swifts (Aves: Apodidae)DOI: info:10.5479/si.00810266.27.129Smithsonian Institution Press129–132
Collins, Charles T. 1976. "A Review of the Lower Miocene Swifts (Aves: Apodidae)." In Collected papers in avian paleontology honoring the 90th birthday of Alexander Wetmore. 129–132. Washington, D.C.: Smithsonian Institution Press. In Smithsonian Contributions to Paleobiology, 27. https://doi.org/10.5479/si.00810266.27.129.