1. Animal feeding stuffs. Determination of Nitrogen Content and Calculation of Crude Protein Content. Kjeldahl method. ISO 5983;International Organization for Standardization,1997
2. Animal feeding stuffs. Determination of Moisture and Other Volatile Matter Content. ISO 6496;International Organization for Standardization,1998
3. Water quality. Determination of 33 Elements by Inductively Coupled Plasma Atomic Emission Spectroscopy. ISO 11885;International Organization for Standardization,1998
4. Animal feeding stuffs. Determination of Crude Ash. ISO 5984;International Organization for Standardization,2002
5. Techniques measuring digestibility for the nutritional evaluation of feeds;Khan;Int. J. Agric. Biol.,2003