1. European Pharmacopoeia 5.0, Council of Europe, Strassbourg, 2004. a) p. 2499, b) p. 1961.
2. S. Gorog, (ed.), Identification and Determination of Impurities in Drugs, 2000, Elsevier, Amsterdam, Chapter 4. Identification, semiquantitative and quantitative determination of inorganic impurities.
3. Electrothermal atomic absorption spectrometric determination of lead in calcium drug samples by direct atomization technique
4. Determination of heavy-metal impurities of ferrous fumarate by atomic spectroscopy;Veres;Magy. Kem. F.,1992
5. Medicinal herbal extracts — renal friend or foe? Part one: the toxicities of medicinal herbs;Wojcikowski;Nephrology,2004