Swengel, S. R., & Swengel, A. B. Status and Trend of Regal Fritillary (Speyeria idalia) (Lepidoptera: Nymphalidae) in the 4th of July Butterfly Count Program in 1977–2014. Wiley.
Chicago Style (17th ed.) CitationSwengel, Scott R., and Ann B. Swengel. Status and Trend of Regal Fritillary (Speyeria Idalia) (Lepidoptera: Nymphalidae) in the 4th of July Butterfly Count Program in 1977–2014. Wiley.
MLA (9th ed.) CitationSwengel, Scott R., and Ann B. Swengel. Status and Trend of Regal Fritillary (Speyeria Idalia) (Lepidoptera: Nymphalidae) in the 4th of July Butterfly Count Program in 1977–2014. Wiley.
Warning: These citations may not always be 100% accurate.