1. Anon.. 1997. BioBase 1997, Register biodiversiteit, CD-Rom. - Centraal Bureau voor de Statistiek Voorburg/Heerlen, Netherlands.
2. - In: Baker, H. G. and Stebbins, G. L. (eds), The genetics of colonizing species. Academic Press 1965..
3. Local avian assemblages as random draws from regional pools;Blackburn,2001
4. Relationship between abundances and life histories of British birds;Blackburn,1996