1. Die Biber in Lettland;Balodis,1992
2. Beavers in Latvia;Balodis,1995
3. Ergänzungen zur einstige Verbreitung des Bibers, Castor fiber (Linné, 1758);Boessneck;Säugetierkundliche Mitteilungen,1974
4. Beaver colony responses to fertility control: evaluating a concept;Brooks;Journal of Wildlife Management,1980
5. Canadian and European beavers in Russian North-west (distribution, number, comparative ecology);Danilov,1995