Bertrand, Claudia, Janzen, Daniel H., Hallwachs, Winnie D., Burns, John M., Gibson, Joel F., Shokralla, Shadi, and Hajibabaei, Mehrdad. 2014. "Mitochondrial and nuclear phylogenetic analysis with Sanger and next-generation sequencing shows that, in Area de Conservacion Guanacaste, northwestern Costa Rica, the skipper butterfly named Urbanus belli (family Hesperiidae) comprises three morphologically cryptic species."
Bmc Evolutionary Biology. 14:153–153.
https://doi.org/10.1186/1471-2148-14-153