1. Burton's line in lead poisoning;Pearce;Eur. Neurol.,2007
2. Letters to the Editor: The short-lived Chinese emperors;Zhao;J. Am. Geriatric. Soc.,2006
3. Procedure 121, Time-limit test for heavy elements, 8th revision;Pharmacopoeia of the United States of America,1905
4. The United States Pharmacopeia/The National Formulary, USP 32/NF 27, The United States Pharmacopeial Convention, Rockville, MD, 2009. Chapter 231, Heavy Elements, pp. 134–136.
5. the USP Metal Impurities Advisory Panel. Metal Impurities in Food and Drugs;Abernethy;Pharm. Res.,2010