1. Observational study of behaviour: sampling methods;Altman;Behaviour,1974
2. Anciães, M. 2005. Evolution of visual signals and the ecological niches among manakins (Aves: Pipridae) from the Ilicura-Corapipo clade. Ph.D. thesis, The University of Kansas.
3. Sexual Selection;Andersson,1994
4. Mate Choice;Bradbury,1983
5. Signals, signal condition and the direction of evolution;Endler;American Naturalist,1992