1. Wolański N (2005) Biological development of human being. PWN, Warszawa (in Polish)
2. The Nutrition Digest of Essential Nutrients (2005) Enerex Botanicals Ltd., Canada. Available from: http://www.enerex.ca/products/Essential Nutrients Book Online Version2.pdf (access 08.06.2006)
3. Radomska K, Graczyk A, Konarski J (1991) Hair analysis as the method of estimate of mineral metabolism of human body. Pol Tyg Lek 46:479–481 (in Polish)
4. Prasad A (1977) Trace elements in human health and disease. Academic Press, New York
5. Hambidge KM (1982) Hair analyses: worthless for vitamins, limited for minerals. Am J Clin Nutr 36:943–949