1. Tejsten Cepphus grylle som ynglefugli i Danmark. (Breeding numbers and habitat selection of Danish Black Guillemots Cepphus grylle;Asbirk;Dansk orn. Foren. Tidsskr.,1978
2. Some behaviour patterns of the Black Guillemot Cepphus grylle. Dansk orn;Asbirk;Foren Tidsskr.,1979a
3. The adaptive significance of the reproductive pattern in the Black Guillemot Cepphus grylle. Vidensk, Meddr;Asbirk;Dansk naturh. Foren.,1979b
4. Gryllteisten Cepphus grylle in einem Randgebiet: Nahrung, Brutresultat, Tagesrhythmus und Ansiedlung. (The Black Guillemot Cepphus grylle in a peripheral area: food, breeding performance, diurnal rhythm and colonization);Bergman;Commentat. Biol.,1971
5. Egg formation and the pre-laying period of the Common Guillemot Uria aalge;Birkhead;J. Zool. Lond.,1987