1. The Nutrient Requirements of Farm Livestock. No. 1. Poultry,1975
2. Ash, W. J., 1976. Raising ducks. US Dept. Agric. Farmer’s Bull. No. 2215.
3. Official Methods of Analysis,1980
4. Nutritional and metabolic interrelationships among sulfur compounds in avian nutrition;Baker;Fed. Proc.,1976
5. Quantitative Aspects of Methionine Metabolism;Benevenga,1983