1. United Nations, Department of Economic and Social Affairs PD. International Migration Report 2015: Highlights. 2016.
http://www.un.org/en/development/desa/population/migration/publications/migrationreport/docs/MigrationReport2015_Highlights.pdf
. Accessed 25 July 2018.
2. Eurostat. Migration and Migrant Population Statistics. 2017.
http://ec.europa.eu/eurostat/statistics-explained/index.php/Migration_and_migrant_population_statistics
. Accessed 25 July 2018.
3. Eurostat. Population and Population Change Statistics. 2017.
http://ec.europa.eu/eurostat/statistics-explained/index.php/Population_and_population_change_statistics
. Accessed 25 July 2018.
4. International Organization for Migration. Global Migration Trends Factsheet. IOM's Global Migration Data Analysis Centre (GMDAC). 2015;13:45.
http://gmdac.iom.int/global-migration-trends-factsheet
. Accessed 25 July 2018.
5. Liu Y, Weinberg MS, Ortega LS, Painter JA, Maloney SA. Overseas screening for tuberculosis in U.S.-bound immigrants and refugees. N Engl J Med. 2009;360:2406–15.