PubMed Dietary Supplement Subset from the U.S. National Institutes of Health Office of Dietary Supplements and United States National Library of Medicine
Marcus DM, Grollman AP (Disember 2002). "Botanical medicines--the need for new regulations". The New England Journal of Medicine. 347 (25): 2073–6. doi:10.1056/NEJMsb022858. PMID12490692.