https://www.businessinsider.com/the-15-least-free-countries-in-the-world-2015-1

https://www.lifehack.org/470813/10-toughest-borders-in-the-world

https://www.businessinsider.com/the-15-least-free-countries-in-the-world-2015-1

https://www.insidermonkey.com/blog/15-countries-with-the-strictest-customs-border-control-and-airport-security-in-the-world-605878/?singlepage=1

https://www.australianfrequentflyer.com.au/which-countries-ban-citizens-leaving/

https://en.wikipedia.org/wiki/Illegal_emigration#:~:text=Restrictive%20exit%20visas,-See%20also%3A%20Kafala&text=Lebanon%2C%20Saudi%20Arabia%2C%20Jordan%2C,workers%2C%20citizens%2C%20or%20visitors.

https://www.quora.com/Oppression-Which-countries-do-not-allow-some-of-their-citizens-to-leave-and-why

https://ciaotest.cc.columbia.edu/journals/wpj/v30i1/f_0033044_26898.pdf

https://www.businessinsider.com/eritrea-the-african-nation-where-you-need-a-permit-to-have-dinner-with-friends-2012-9

https://www.haaretz.com/eritrea-the-north-korea-of-africa-1.5156998

https://www.cfr.org/global-conflict-tracker/conflict/north-korea-crisis#:~:text=In%20addition%20to%20U.S.%20troops,armed%20borders%20in%20the%20world.