F. Li, P. Harmer, K. Fitzgerald, E. Eckstrom, R. Stock, J. Galver, G. Maddalozzo and S. S. Batya, “Tai Chi and Postural Stability in Patients with Parkinsons Disease,” New England Journal of Medicine, Vol. 366, No. 6, 2012, pp. 511-519. doi10.1056/NEJMoa1107911 - References - Scientific Research Publishing