| 1 | 1. Nutrient Requirements of Dairy Cattle Seventh Revised ed. 2001.National Academy Press. 2101. Washington D.C. 20418. |
| 2 | 2. Nutrient Requirements of Beef Cattle Seventh Rev. Ed. Updated 2000. NRC. ISBN 0 309 59241 0 |
| 3 | 3. Nutrient Requirements of Small Ruminants. 2007 NRC |
| 4 | 4. Nutritional ecology of the ruminant. Van Soest. Second ed. 1983.O&B Books, Inc. ISBN 0-9601586-0-X |
| 5 | 5. Ruminant Nutrition Recommended Allowances and Feed Tables Ed. R. Jarrige INRA ISBN 0-86196-247-8 |