1. Global tuberculosis report 2012. Switzerland: World Health Organization. 2012. http://apps.who.int/iris/bitstream/10665/75938/1/9789241564502_eng.pdf . Accessed 28 May 2015.
2. Walter ND, Painter J, Parker M, Lowenthal P, Flood J, Fu Y, et al. Persistent latent tuberculosis reactivation risk in United States immigrants. Am J Respir Crit Care Med. 2014;189:88–95.
3. Sudre P, ten Dam G, Kochi A. Tuberculosis: a global overview of the situation today. Bull World Health Organ. 1992;70:149–59.
4. Canadian Tuberculosis Standards. 7th edn. Ottawa (ON): Canadian Thoracic Society. 2013. http://www.respiratoryguidelines.ca/tb-standards-2013 . Accessed 28 May 2015.
5. Framework towards TB elimination in low-incidence countries. Switzerland: World Health Organization. 2014. http://apps.who.int/iris/bitstream/10665/132231/1/9789241507707_eng.pdf?ua=1 . Accessed 28 May 2015.