Losada H, Vieyra J, Rivera J, Martínez H, Pealing R, Cortés J and Arias L 1997:
Cattle behaviour as an indicator of animal welfare in the dairy systems of Iztapalapa, Mexico City.
Livestock Research for Rural Development. Volume 9, Article #32.
Retrieved
, from http://www.lrrd.org/lrrd9/4/mex941.htm