1. International Conference on Harmonisation (ICH), Guidance Q3A, Impurities in New Drug Substances. Federal Register, 4 Jan. 1996 (61 FR 371) (available at http://www.ifpma.org/ich1.html).
2. US Food and Drug Administration (FDA) Center for Drug Evaluation and Research (available at http://www.fda.gov/cder/guidance/2452fnl.htm).
3. International Federation of Pharmaceutical Manufacturers Association (available at http://www.ifpma.org).
4. Assessment of chromatographic peak purity of drugs by multivariate analysis of diode-array and mass spectrometric data