6K.-H. Jeppsson. Carbon Dioxide Emission and Water Evaporation from Deep Litter Systems[J].Journal of Agricultural Engineering Research, 2000,77 ( 4 ) : 429-440.
7P. Kapuinen. Deep Litter Systems for Beef Cattle housed in Uninsulated Barns, Part 2:Temperatures and Nutrients [J].Journal of Agricultural Engineering Research, 2001,80( I ) : 87-97.
8R. S. Morrison, et al. The social and feeding behaviour of growing pigs in deep-litter, large group housing systems [J]. Applied Animal Behaviour Science, 2003,82 : 173-188.