Zhao, J., Wang, X. Julkaisussa China Winter Sports (2013)
MacMahon, S., Norton, R, Perkovic, V. Julkaistu 1999
Xia, J., Wang, X. Julkaisussa Journal of Tianjin University of Sport (2014)
Sun, Y., Chang, C. Julkaisussa Journal of Capital University of Physical Education and Sports (2014)