
http://publications.iom.int/system/files/pdf/global_migration_indicators_2018.pdf

https://www.aicgs.org/publication/refugees-terrorism-and-a-failing-security-architecture/

http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6452&CESifoWP.search=+