1. For drug makers, good times yield to a new profit crunch;Harris;Wall Street J,2002
2. New Drug Development;USGAO,2006
3. Lessons from 60 years of pharmaceutical innovation;Munos;Nat. Rev. Drug Discov.,2009
4. PhRMA (2014) Pharmaceutical industry profile. http://www.phrma.org/sites/default/files/pdf/2014_PhRMA_PROFILE.pdf
5. National Science Foundation Federal funds for R&D. Available at: http://www.nsf.gov/statistics/fedfunds