1. BMDP Statistical Software;BMDP,1983
2. Practical hygienic control of milk contamination and udder infections. National Mastitis Council;Bushnell,1984
3. The importance of hygienic procedures in controlling mastitis;Bushnell,1984
4. Environmental factors in bovine mastitis;Carroll,1977
5. Measuring the impact of different veterinary service programs on diary herd health and milk production;Goodger,1985