1. Newzoo. Global esports market report. 2019. https://resources.newzoo.com/hubfs/2019_Free_Global_Esports_Market_Report.pdf?utm_campaign=Esports%20Market%20Report. Accessed 7 Jan 2020.
2. Kent S. The ultimate history of video games. New York: Random House International; 2002.
3. Hilgers J. Esports games tiers. 2017. https://esportsobserver.com/esports-games-tiers. Accessed 7 Jan 2020.
4. Colzato LS, van Leeuwen PJ, van den Wildenberg WP, Hommel B. DOOM’d to switch: superior cognitive flexibility in players of first person shooter games. Front Psychol. 2010;1:8. https://doi.org/10.3389/fpsyg.2010.00008.
5. Fillari A. Battle royale games explained: Fortnite, PUBG, and what could be the next big hit. 2019. https://www.gamespot.com/articles/battle-royale-games-explained-fortnite-pubg-and-wh/1100-6459225/. Accessed 7 Jan 2020.