Attributes / relations provided by
♦ 1Frugivory, external morphology and digestive system in Mediterranean sylviid warblers Sylvia spp., Pedro Jordano, IBIS 129: 175-189 (1987)
♦ 2del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.).
Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.