1. Aeberhard, K., Bruckmaier, R. and Blum, J., 1997. High producing cows in Switzerland. Agrafor, 4, 277–280
2. Agyemang, K. and Nkhonjera, L.P., 1990. Productivity of crossbred cattle in smallholder farms in Southern Malawi. Tropical Animal Health and Production, 22, 9–16
3. Blood, D.C., Radostitis, O.M. and Gay, C.C., 1997. Veterinary Medicine. Textbook of the Disease of Cattle, Sheep, Goats, Pigs and Horses, 8th edn, (WB Saunders, St Louis, MO, USA)
4. Elbs Bott, K. and Distl, O., 1994. Commercial crossbreeding of German brown with Blonde d'Aquitaine and German Simmental. 2. Influence of dystocia and sire breed on fertility, milk-production and survival in the consecutive lactation. Zuchtungskunde, 66, 124–135
5. Bruun, J., Ersboll, A.K. and Alban, L., 2002. Risk factors for metritis in Danish dairy cows. Preventive Veterinary Medicine, 54, 179–190