"삼성전기 서윤희 선수". Badmintonkorea.co.kr (in Korean). 30 April 2012. Archived from the original on 5 May 2018. Retrieved 5 May 2018.
chinadaily.com.cn
Cheng Xiangfeng (June 27, 2008). "Overseas Chinese still main threats". China Daily. Retrieved June 7, 2010.("Pi played badminton for France at the 2004 Athens Olympics, losing to Seo Yoon-hee of South Korea in the round of 32.")
dailytimes.com.pk
"China's Gong makes rivals sweat". Daily Times (Pakistan). August 15, 2004. Retrieved June 7, 2010.("South Korea’s Seo Yoon-Hee provided the tournament’s first upset, defeating China-born French number eight seed Pi Hongyan in a gripping three-setter. Ranked 28th in the world, Seo showed plenty of guts and determination and will fancy her chances when she meets Petya Nedelcheva in the next round.")
Getty Images Photo ("Bulgaria's Petya Nedelcheva celebrates after beating South Korea's Seo Yoon Hee in the women's singles round of 16 of the Olympic Games badminton competition, at the Goudi Olympic Hall in Athens 15 August 2004. Nedelcheva beat Seo 7-11, 11-5, 11-8")
