1. Ravens in winter;B Heinrich,1989
2. The raven, a natural history in Britain and Ireland;D Ratcliffe,1997
3. A raven roost in Devon.;HG Hurrell;Br Birds,1956
4. Foraging by common ravens in the presence and absence of territory holders, an experimental analysis of social foraging.;JM Marzluff;Anim Behav,1991
5. Common Ravens are attracted by appeasement calls of food discoverers when attacked.;B Heinrich;Auk,1993