Corrigan DK, Salton NA, Preston C, Piletsky S. Towards the development of a rapid, portable, surface enhanced Raman spectroscopy based cleaning verification system for the drug nelarabine. J Pharm Pharmacol. 2010 Sep;62(9):1195–200. doi: 10.1111/j.2042-7158.2010.01152.x. PMID: 20796200.