1. FAO. Medicinal plants for forest conservation and health care. Bodeker G, Bhat KKS, Burley J, Vantomme P. (eds). Food and Agriculture Organization of the United Nations, Non-Wood Forest series No. 11. Rome, 1997.
2. Lannoye P. Report on the status of non-conventional medicine. Committee on the Environment, Public Health and Consumer Protection. European Parliament, Document No. PE 216.066/fin. 6 March, 1997.
3. Report of the Commission on Dietary Supplement Labels, US Government Commission on Dietary Supplement Labels (CDSL), 1997.
4. WHO. Regulatory Situation of Herbal Medicines: A Worldwide Review. World Health Organization, Geneva, 1998.