
Meðal hrafna er mjög lítill útlistsmunur á kven- og karlfuglum.
- Bedrosian, B., Loutsch, J. & Craighead. D. (2008). Using Morphometrics To Determine the Sex of Common Raven. Northwestern Naturalist 89(1), 46-52.
- Boarman, W.I. & Heinrich, B. (1999). Common Raven (Corvus corax). Í The Birds of North America, No. 476 (A. Poole & F. Gill ritstj.). The Birds of North America, Inc, Philadelphia, PA.
- Common Raven. iNaturalist.
- Hinterland Who's Who - Common Raven. Canadian Wildlife Federation.
- Corvus corax ad berlin 090516.jpg. Wikimedia Commons. Höfundur myndar R. Altenkamp. Birt undir CC BY-SA 3.0 DEED leyfi. (Sótt 22.5.2024).