1. Akester, A. A. and Titchen, D. A. (1969). Radiographic studies of the reticulorumen in sheep. J. Anat., 104, 137–151
2. Balch, C. C- (1950). Factors affecting the utilization of food by dairy cows. 1. The rate of passage of food through the digestive tract. Br. J. Nutr., 4, 361–388
3. Balch, C. C. and Campling, R. C. (1965). Rate of passage of digesta through the ruminant digestive tract. In R. W. Dougherty (ed.) Physiology of Digestion in the Ruminant, pp. 108–123 (Washington: Butterworths)
4. Benzie, D. and Phillipson, A. T. (1957). The Alimentary Tract of the Ruminant. (Edinburgh and London: Oliver and Boyd)
5. Bueno, L. (1975). Motor and digestive functions of the omasum. Thesis Sci. Nat., Universite P. Sabatier, Toulouse