1. Aljazeera. (2020). WHO: Travel bans cannot be indefinite, countries must fight virus. https://www.aljazeera.com/news/2020/7/27/who-travel-bans-cannot-be-indefinite-countries-must-fight-virus
2. BBC News. (2021). Россия ограничила перелеты с Турцией [Russia restricts flights with Turkey]. https://www.bbc.com/russian/news-56716919
3. Brumfiel, G. & Wilburn, T. (2020). Countries slammed their borders shut to stop Coronavirus. But is it doing any good? NPR https://www.npr.org/sections/goatsandsoda/2020/05/15/855669867/countries-slammed-their-borders-shut-to-stop-coronavirus-but-is-it-doing-any-goo
4. The Conversation. (2021). Closed borders, travel bans and halted immigration: 5 ways COVID-19 changed how – And where – People move around the world. https://theconversation.com/closed-borders-travel-bans-and-halted-immigration-5-ways-COVID-19-changed-how-and-where-people-move-around-the-world-157040
5. The main trends in the Russian tourism and hospitality market from the point of view of Russian travel agencies