"Yvonne van Gennip". The Beijing Organising Committee for the Games of the XXIX Olympiad. Archived from the original on 3 February 2009. Retrieved 20 March 2009.
books.google.com
Lund, Mortund (December 2001). "The First Four Olympics". Skiing Heritage Journal. International Skiing History Association: 21. Retrieved 18 April 2011.
"Freestyle Skiing History". The National Post. Toronto. CBC Sports. 4 December 2009. Archived from the original on 28 January 2010. Retrieved 16 March 2010.
Hunt, Thomas M. (2007). "Sports, Drugs, and the Cold War"(PDF). Olympika, International Journal of Olympic Studie. 16 (1). International Centre for Olympic Studies: 22. Archived from the original(PDF) on 23 July 2012. Retrieved 23 March 2009.
"Yvonne van Gennip". The Beijing Organising Committee for the Games of the XXIX Olympiad. Archived from the original on 3 February 2009. Retrieved 20 March 2009.
Hunt, Thomas M. (2007). "Sports, Drugs, and the Cold War"(PDF). Olympika, International Journal of Olympic Studie. 16 (1). International Centre for Olympic Studies: 22. Archived from the original(PDF) on 23 July 2012. Retrieved 23 March 2009.
"Freestyle Skiing History". The National Post. Toronto. CBC Sports. 4 December 2009. Archived from the original on 28 January 2010. Retrieved 16 March 2010.