4Li P J. Exponential growth, animal welfare, environmental and food safety impact: The case of China's livestock production. Journal of agricultural and environmental ethics ,2009,22 ( 3 ) :217 - 240.
5Te Velde H, Aarts N, Van Woerkum C. Dealing with ambivalence : farmers" and eonsumers" perceptions of animal welfare in livestock breed- ing. Journal of agricultural and environmental ethics ,2002,15 (2) :203 -219.