Vocalization and associated behaviors of the sombre hummingbird (Aphantochroa cirrhochloris) and the rufous-breasted hermit (Glaucis hirsutus) - Ferreira, Adriana R. J.; Smulders, Tom V.; Mellom, Claudio V.; Jarvis, Erich D.; Sameshima, Koichi (The american ornithologist's union, 2006)