J. Monge-Nájera, F. Hernández, M. I. González, J. Soley, J. Araya, and S. Zolla, “Spatial distribution, territoriality and sound production by tropical cryptic butterflies (Hamadryas, Lepidoptera: Nymphalidae): implications for the ’’industrial melanism" debate”, Rev. Biol. Trop., vol. 46, no. 2, pp. 297–330, Jun. 1998.