6[8]Lund. V, Algers. B. Research on animal health and welfare in organic farming-a literature review[J]. Livestock Production Science, 2003,80: 55- 68
7[9]Kouba. M. , Quality of organic animal products[J]. Livestock Production Science. 80 (2003) 33-40.
8[10]Bartussek. ,H. A review of the animal needs index (ANI) for the assessment of animals' well being in the housing systems for Austrian proprietary products and legislation[J]. Livestock Production Science, 1999,61:179- 192.