1. Agriculture Canada, 1993. Recommended Code of Practice for Care and Handling of Pigs, Publication no. 1771E, Agriculture Canada, Ottawa, Canada.
2. Agricultural Research Council (ARC), 1981. The Nutrient Requirements of Pigs, Commonwealth Agricultural Bureaux, Slough, UK.
3. BASF, 2001. Fortification en Vitamines des Aliments Porcs et Volailles au Canada. Séminaire Technique. Duval M. (Ed), St-Pie de Bagot, QC, Canada, 17 p.
4. Human tryptophan dioxygenase: a comparison to indoleamine 2,3-dioxygenase;Batabyal;J. Am. Chem. Soc.,2007
5. Oestrogens and vitamin B6: actions and interactions;Bender;World Rev. Nutr. Diet.,1987