Bjorn Petersen, 1963. The male genitalia of some Colias species.Journal of Research on the Lepidoptera 1: 135-156.[1]Archived 2017-06-03 at the Wayback Machine
Paul C. Hammond, 1990 Patterns of geographic variation and evolution in polytypic butterflies Journal of Research on the Lepidoptera 29(1-2):54-76.
[2]Archived 2013-12-03 at the Wayback Machine
Bjorn Petersen, 1963. The male genitalia of some Colias species.Journal of Research on the Lepidoptera 1: 135-156.[1]Archived 2017-06-03 at the Wayback Machine
Paul C. Hammond, 1990 Patterns of geographic variation and evolution in polytypic butterflies Journal of Research on the Lepidoptera 29(1-2):54-76.
[2]Archived 2013-12-03 at the Wayback Machine