1. Association of Official Analytical Chemists (AOAC), 1990. Assoc. of Official Anal. Chem., 15th Edition. Washington, DC, pp. 69–89.
2. The calorimetric determination of lactic acid in biological material;Baker;J. Biol. Chem.,1961
3. Butler, G.W., Bailey, R.W., 1973. Criteria for assessing the efficiency of the fermentation process. In: Butler, G.W., Bailey, R.W. (Eds.), Chemistry and Biochemistry of Herbage, Vol. 3. pp. 33–80.
4. Chamberlain, A.T., Wilkinson, J.M., 1996. The ideal silage. In: Chamberlain, A.T., Wilkinson, J.M. (Eds.), Feeding the Dairy Cow. Chalcombe Publications, Lincol, UK, pp. 28–30.
5. Microdiffussion methods: ammonia and urea using buffer absorbents (revised methods for ranges greater than 10 (g N);Conway;Biochem. J.,1942