1. IFPI. 2020. IFPI issues annual Global Music Report (2020). https://www.ifpi.org/ifpi-issues-annual-global-music-report/. Retrieved February 2021
2. Witkowski, W.: Videogames are a bigger industry than movies and North American sports combined, thanks to the pandemic (2021). https://www.marketwatch.com/story/videogames-are-a-bigger-industry-than-sports-and-movies-combined-thanks-to-the-pandemic-11608654990. Retrieved February 2021
3. Fullerton, T., Swain, C.: Game Design Workshop: A Playcentric Approach to Creating Innovative Games (2nd. edn.). Gama Network Series (2008)
4. Johnson, D., Watling, C., Gardner, J., Nacke, L.E.: The edge of glory: the relationship between metacritic scores and player experience. In: Proceedings of the first ACM SIGCHI Annual Symposium on Computer-Human Interaction in Play, pp. 141–150 (2014)
5. Orland, K.: Steam Gauge: Do strong reviews lead to stronger sales on Steam? https://arstechnica.com/gaming/2014/04/steam-gauge-do-strong-reviews-lead-to-stronger-sales-on-steam/ (2014). Retrieved February 2021