1. Aspelin, E.H., 1991. Avlsarbeidets virkning på søyevektene. C and. Agric. Dissertation. Dept. Animal Science, Agr. Univ. of Norway, Ås, pp. 58, in Norwegian
2. A review of the genetic and physiological relationships between growth and reproduction in mammals;Brien;Anim. Breed. Abstr.,1986
3. Genetic, phenotypic and environmental parameters for productivity traits of ewes;Eikje;Acta Agric. Scan.,1975
4. Larsgard, A.G., 1994. Verdien av innkryssing av østfrisisk mjølkesau i norsk sau. Husdyrforsøksmøtet 1994, pp. 402–406, in Norwegian
5. Lewer, P., 1986. Selection for liveweight II. Correlated responses. In: Are Big Sheep Best? Proc. of a seminar held 28th August 1986 in Australia, Australian Society of Animal Production, Animal Breeding Res. Inst., Katanning, W.A., Australia., pp. 31–37