1. Arudou, D. (2018). Warning to Naomi Osaka: Playing for Japan can seriously shorten your career. The Japan Times.
2. ATP Tour (n.d.). Kei Nishikori: Titles & finals. https://www.atptour.com/en/players/kei-nishikori/n552/titles-and-finals.
3. Badenhausen, K. (2020, May 22). Naomi Osaka is the highest-paid female athlete ever, topping Serena Williams. Forbes. https://www.forbes.com/sites/kurtbadenhausen/2020/05/22/naomi-osaka-is-the-highest-paid-female-athlete-ever-topping-serena-williams/#63e0e4151fd3
4. Badenhausen, K., & Forbes staff (2020, May 21). Highest-paid athletes in the world. Forbes. https://www.forbes.com/athletes/#3581d62355ae
5. Bien-Aimé, S., Jia, H., & Yang, C. (2019). The female hero through the cultural lens: Comparing framing of Li Na in Chinese and Western media. In R. J. Lake (Ed.), The Routledge handbook of tennis: History, culture and politics (pp. 86–95). Routledge.