1. Neimann-Sørensen A. 1969. In Crop Conservation and Grassland. Proc. 3rd Meeting Euro. Grassld Fedn, p. 105.
2. National Academy of Sciences — National Research Council. 1964. Joint United States-Canadian Tables of Feed Composition, Publ. NAS-NRC, No. 1232.
3. Minson D. J. 1962. The effect of grinding, pelleting and wafering on the feeding value of roughages, Anim. Res. Inst., Canada Dept. Agric, Rev. Cotttr. No. 84.
4. Khalifa H. A. A. 1970. The use of high concentrate low roughage diets in dairy cow nutrition. Ph.D. Thesis, University of Newcastle upon Tyne.