1. The United States Pharmacopeia/The National Formulary, USP 37/NF 32, 2014. The official compendia of standards. In: Rockville, (Ed.) ch 232—Elemental Impurities—Limits
2. The United States Pharmacopeia/The National Formulary, USP 37/NF 32, 2014. The official compendia of standards. In: Rockville, (Ed.) ch 233—Elemental Impurities—Procedures.
3. The use of atomic spectroscopy in the pharmaceutical industry for the determination of trace elements in pharmaceuticals
4. Overview of microwave-assited sample preparation;Walter,1997