1. World Health Organization. How to develop and implement a national drug policy. World Health Organization; 2001.
2. Laing R, Waning B, Gray A, Ford N, t Hoen E. 25 years of the WHO essential medicines lists: progress and challenges. Lancet. 2003;361(9370):1723–9.
3. Attridge CJ, Alexander SP. Improving access to medicines in developing countries. Washington, DC: The World Bank; 2005.
4. World Health Organization. WHO model list of essential medicines: 18th list. 2013.
5. Opderbeck DW. Patents, essential medicines, and the innovation game. Vand L Rev. 2005;58:501.