Cladistic analysis of Heliconius butterflies and relatives (Nymphalidae: Heliconiiti): a revised phylogenetic position for Eueides based on sequences from mtDNA and a nuclear gene
A. V. Z. Brower and M. G. Egan
Proc Biol Sci. 1997 July 22; 264(1384): 969–977. doi: 10.1098/rspb.1997.0134.